Ch-1: Chemical Reactions & Equations
Burning of a magnesium ribbon in air and collection of magnesium
oxide in a watch-glass
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with
sandAb
paper.
Chalo
Ise AASAN BHASHA MEI Samajhte hai :
Hold the magnesium
ribbon with
a pair
tongs , and start
heating. its other end.
Take about
2 cm
longofmagnesium
ribbon
The Magnesium Ribbon starts burning.
Clean it with sand paper.
BUT IT'S NOT BURNING ALONE.
HoldIt the
with a pair
of .tongs , and start heating its
startsmagnesium
burning with a ribbon
WHITE DAZZLING
FLAME
other
end.hold it over a Watch Glass
And now to collect the Magnesium Oxide
Powder
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
Q: Why Magnesium ribbon is cleaned before burning in the air ?
Ans: The magnesium ribbon which we use usually has a coating of ‘magnesium oxide’
on its surface which is formed by the slow action of oxygen of air on it. So, before
burning in air, the magnesium ribbon is cleaned by rubbing with a sand paper. This is
done to remove the protective layer of magnesium oxide from the surface of
magnesium ribbon so that it may readily combine with the oxygen of air (on heating).
Q: Why the magnesium ribbon should be burned by keeping it as far as
possible from the eyes?
Ans: The dazzling (very bright) white light given out during the burning of magnesium
ribbon is harmful to the eyes. So, the magnesium ribbon should be burned by keeping
it as far as possible from the eyes.
" 10th मतलब ?? - Shobhit Nirwan "
Formation of Precipitate
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
(i) Take some lead nitrate solution in a test-tube (or a
beaker).
(ii) Add potassium iodide solution to it.
(iii) A yellow precipitate of lead iodide is formed at once.
(iv) A change in colour (from colourless to yellow) also
takes place in this chemical reaction.
Chemical Reactions that evolve Gases AND RIse In Temperature
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
(Take some Zinc Granules in a Conical Flask
Now on Adding the Sulphuric Acid you will See a Magic.
As You will see the bubbles of HYDROGEN GAS forming around the zinc metal
We verified that it is Hydrogen gas because its bubbles burnt with pop sound
when passed through soap solution (As shown below diagram)
Also, if we will touch the flask with our hands we will see that it is too HOT.
So we get to know that along with evolution of gas temperature also rises in
the Chemical Reactions.
" 10th मतलब ?? - Shobhit Nirwan "
Decomposition reaction of ferrous sulphate.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 grams of Ferrous Sulphate Crystals in a DRY Boiling Tube.
They are originally Green In Colour
Heat the boiling tube over a burner
Now You will again see the magic.
As the green colour first changes to White And then Finally a Brown Solid is
formed(which is ferric oxide)
So the main observation of this activity is that the smell of burning Sulphur
comes out along with the colour change from Green to White and then Brown.
Decomposition reaction of lead nitrate
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 grams of lead nitrate powder in a boiling tube. Lead nitrate is a
colourless compound.
Hold the boiling tube in a test-tube holder and heat it over a burner.
Brown fumes of nitrogen dioxide gas are evolved which fill the boiling tube.
If a glowing splinter is held over the mouth of the boiling tube, it catches fire and
starts burning again. This shows that oxygen gas is also evolved during this
reaction.
A yellow solid is left behind in the boiling tube. This is lead monoxide (Please
note that lead monoxide is reddish-brown when hot but yellow when cold).
" 10th मतलब ?? - Shobhit Nirwan "
Decomposition of silver chloride is caused by light
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 grams of silver chloride in a china dish. It is white in colour.
Place this china dish in sunlight for some time .
We will find that white silver chloride turns greyish white (due to the formation of
silver metal).
Silver bromide also behaves in the same way as silver chloride with light energy.
Displacement reaction between iron (nail) and copper sulphate
solution.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 10 mL of copper Sulphate solution in a test tube.
Its original colour is Deep Blue
Now take a big iron nail and clean it same like u did with Magnesium Ribbon
using the sand paper.
Now put the iron nail in the solution and then see the magic.
After sometime like half an hour we will see that the iron nail would be covered
with red-brown layer.
And this layer would be of our another metal that is Copper.
So Finally we will see that the original Deep blue colour has faded and the
solution turns to light Green Colour.
" 10th मतलब ?? - Shobhit Nirwan "
Double displacement reaction between barium chloride and
sodium sulphate.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take 3mL of Sodium Sulphate solution in a test tube .
And take 3mL of Barium Chloride but in another test tube .
Add Barium Chloride solution to Sodium Sulphate solution
And the magic we see is now of White colour as a White Precipitate is left over in
the Test Tube.
Oxidation of copper to copper oxide
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 1 gram of copper powder in a china dish. It is redbrown in colour.
Heat the china dish strongly over a burner (see Figure 55).
A black substance is formed. This black substance is copper oxide
" 10th मतलब ?? - Shobhit Nirwan "
Ch-2: Acids, Bases and Salts
Reaction of zinc granules with dilute sulphuric acid and testing
hydrogen gas by burning
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other
end.
Chalo Ab Ise AASAN
BHASHA
MEI Samajhte hai :
Take a few pieces
zinc granulesRibbon
in a boiling
tubeburning.
and add about 5 mL of
TheofMagnesium
starts
dilute sulphuric acid
to itIT'S
.
BUT
NOT BURNING ALONE.
We will observe
theburning
formation
of gas
bubblesDAZZLING
on the surface
of zinc. granules.
It starts
with
a WHITE
FLAME
Pass
gastobeing
formed
the soap
solution
taken inhold
a trough
(by a
Andthe
now
collect
thethrough
Magnesium
Oxide
Powder
it over
means of a glass delivery tube). Gas filled bubbles are formed in the soap
Watch Glass
solution which rise into the air.
Bring a burning candle near a gas-filled soap bubble. The gas present in soap
bubble burns with a ‘pop’ sound (making a little explosion).
Only hydrogen gas burns making a ‘pop’ sound. This shows that hydrogen gas
is evolved in the reaction of dilute sulphuric acid with zinc metal (taken in the
form of zinc granules)
TEST for CO2 gas
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take a boiling tube and put about 0.5 g of sodium carbonate in it.
Chalo
AASAN
BHASHA
Samajhte
hai : a
Add about
2 mLAb
of Ise
dilute
hydrochloric
acid inMEI
the boiling
tube (through
Take about 2 cm long magnesium ribbon .
thistle funnel)
Clean
it with sand
We will observe that brisk
effervescence
of a paper.
gas is produced.
gas throughribbon
lime water.
Thea lime
turns milky
that it is its
HoldPass
the the
magnesium
with
pairwater
of tongs
, and(showing
start heating
carbon dioxide gas).
other end.
Keep on passing
carbon
dioxide
through
milky lime
water for some more
The Magnesiumgas
Ribbon
starts
burning.
time. The lime water becomes clear again.
BUT IT'S NOT BURNING ALONE.
This shows that the white precipitate of calcium carbonate dissolves on passing
It starts burning with a WHITE DAZZLING FLAME .
excess of carbon dioxide gas. We can repeat this experiment by using sodium
And now to collect
the
Oxide
Powder
it over a
hydrogencarbonate
in place
ofMagnesium
sodium carbonate.
Again
we willhold
get carbon
Watch
Glass
dioxide gas which will turn lime water
milky.
On passing excess of carbon dioxide,
the milky lime water will become clear again.
Activity to investigate whether all compounds containing hydrogen
are acidic.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Chalo
Ab Ise 2AASAN
BHASHA
MEI Samajhte
hai : .
Take
about
cm long
magnesium
ribbon
(i) Take solutions of hydrochloric acid, sulphuric acid, glucose and alcohol. All
Clean it with sand paper.
these are hydrogen containing compounds.
Hold the magnesium ribbon with a pair of tongs , and start heating its
(ii) Fix two iron nails on a rubber cork and place the cork in a beaker.(Fig (a) on
other end.
next page)
Theto
Magnesium
Ribbon
starts
burning.
(iii) Connect the nails
the two terminals
of a 6
volt battery
through a switch and
BUT IT'S NOT BURNING ALONE.
a bulb.
(iv) Pour some
dilute burning
hydrochloric
acidasolution
solution) inFLAME
the beaker
It starts
with
WHITE(HCl
DAZZLING
. and
switch
the to
current.
The the
bulb Magnesium
starts glowing.(Fig
a) Powder hold it over a
Andon
now
collect
Oxide
This shows that hydrochloric acid solution
Watch taken
Glassin the beaker conducts electricity.
If we repeat this experiment by taking sulphuric acid solution in the beaker, the
bulb glows again. This shows that sulphuric acid solution also conducts electricity.
In fact, all the acid solutions conduct electricity.
(v) Let us now take glucose solution (C6H12O6 solution) in the beaker and switch
on the current. The bulb does not glow in this case (Fig b). This shows that glucose
solution does not conduct electricity.
If we repeat this experiment by taking alcohol solution in the beaker, the bulb does
not glow again. This shows that alcohol solution also does not conduct electricity.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
Experiment to show that acids do not show acidic behaviour
without water.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other
end.MEI Samajhte hai :
Chalo Ab Ise AASAN
BHASHA
Ribbon
burning.
Take about 1 g The
SolidMagnesium
sodium chloride
(NaCl) instarts
clean and
dry boiling tube and add
conc. sulphuric acid
to it IT'S
carefully
fit the rubber
con over glass tube.
BUT
NOTand
BURNING
ALONE.
Conc. sulphuric
acid
reacts with
Sodium
chloride
to form hydrogen
gas.
It starts
burning
with
a WHITE
DAZZLING
FLAMEchloride
.
The hydrogen
coming outOxide
of the open
enclave.
And
now to chloride
collectgas
thestarts
Magnesium
Powder
hold it over a
Hold a 'dry' blue litmus paper in HCl gas. So there is no change in the colour of dry
Watch Glass
blue litmus paper. This show shows that HCl gas does not behave as an acid to
the absence of water.
We now hold a 'moist' blue litmus paper in HCl gas, Now we will see the 'moist'
blue litmus paper to red. This shows that HCl gas show acidic behaviour in the
presence of water.
Conclusion: HCl gas does not shout acidic behaviour in absence of water but it
shows acidic behaviour in presence of water.
" 10th मतलब ?? - Shobhit Nirwan "
Adding Acid/Base in Water
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
Chalo
Ab Ise AASAN
Samajhte hai
:
It starts
burning
with aBHASHA
WHITEMEI
DAZZLING
FLAME
.
The process of dissolving an acid or a base in water is a highly exothermic one.
And now to collect the Magnesium Oxide Powder hold it over a
AnsWatch Glass
i. Yes beaker becomes hot on adding H2SO4 (Acid)
ii. Exothermic reaction took place.
Determining Family of Salts
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Chalo AbClean
Ise AASAN
BHASHA
Samajhte hai :
it with
sandMEI
paper.
Ans-the
(i. &magnesium
ii.) Formulas and
identificationHold
ribbon
with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
iii. Na2SO4, NaCI, NaNO3 and Na2CO3 belong to the family of sodium salts.
K2SO4, Na2SO4, CaSO4, MgSO4, CuSO4 belong to the family of sulphate
salts.
NaCI and KCI belong to the family of chloride salts.
" 10th मतलब ?? - Shobhit Nirwan "
pH, Acids and Bases Used
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
ChaloMagnesium
Ab Ise AASANRibbon
BHASHA starts
MEI Samajhte
hai :
The
burning.
AnsBUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
Are the Crystals of Salts really Dry?
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
Chalo
Ab Ise AASAN Ribbon
BHASHA MEI
Samajhte
hai :
The Magnesium
starts
burning.
i) Take a tube, add few crystals of copper sulphate and heat it.
BUT IT'S NOT BURNING ALONE.
ii) On heating copper sulphate will start appearing white.
It starts burning with a WHITE DAZZLING FLAME .
iii) Copper sulphate crystals contain water of crystallisation. When heated the
And now
to collect
theand
Magnesium
crystals,
this water
is removed
the salt turnsOxide
white.Powder hold it over a
Watch
Glass
iv) On adding 2-3 droplets of water,
Copper
sulphate crystals restore its blue
colour.
" 10th मतलब ?? - Shobhit Nirwan "
Ch-3: Metals and Non-Metals
Chalo Ab
AASAN
BHASHA
MEI
Samajhte
hai :
Metals,
in Ise
their
pure state,
have
a shining
surface.
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
BUT IT'S NOT BURNING ALONE.
Metals, in their pure state, have a shining surface.
It starts burning with a WHITE DAZZLING FLAME .
So, before rubbing and cleaning with sample paper, metals had less shiny surface.
And
now to
Oxide
Powder
After
rubbing
andcollect
cleaningthe
withMagnesium
sand paper, they'll
become
morehold
shiny.it over a
Watch Glass
Metals are *generally* hard
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
BUT IT'S NOT BURNING ALONE.
i. Metals like iron, copper, aluminium and magnesium are hard to cut with knife.
It starts
burning
a pair
WHITE
DAZZLING
. We
ii. Hold a piece
of sodium
metalwith
with a
of tongs,
put on a FLAME
watch-glass.
And now
Oxide Powder hold it over a
observe
it canto
becollect
cut easilythe
withMagnesium
a knife.
iii. We observed that metals are generally
Watch hard.
GlassThe hardness varies from metal to
metal.
Chalo
Abmetals
Ise AASAN
BHASHA
hai :
Some
can be
beatenMEI
intoSamajhte
thin sheets
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium
starts
burning.
Chalo
Ab Ise AASANRibbon
BHASHA MEI
Samajhte
hai :
We observed that some
metals
be BURNING
beaten into thin
sheets. This property is
BUT
IT'Scan
NOT
ALONE.
called malleability.
It starts burning with a WHITE DAZZLING FLAME .
Gold
and
silver
the most
malleable
metals Oxide Powder hold it over a
And now toare
collect
the
Magnesium
Watch Glass
" 10th मतलब ?? - Shobhit Nirwan "
Metals are good conductors of heat and have high melting points
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium
starts
burning.
Chalo
Ab Ise AASANRibbon
BHASHA MEI
Samajhte
hai :
BUT
IT'S
NOT
BURNING
ALONE.
i. On heating the wire we'll find that the heat from burner will travel in the whole
wire melting
the wax.burning with a WHITE DAZZLING FLAME .
It starts
ii. And
On melting,
pincollect
will drop.
ButMagnesium
metal wire doesn't
melt
becausehold
of high
now to
the
Oxide
Powder
it melting
over a
point of metals.
Watch Glass
iii. We observed that metals are good conductors of heat and have high melting
points
Chalo AbMetals
Ise AASAN
MEI Samajhte hai :
also BHASHA
conduct electricity
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
BUT
IT'S
NOTbetween
BURNING
ALONE.
i. On placing the metal
in the
circuit
terminals
A and B, we find that the
It
starts
burning
with
a
WHITE
DAZZLING
FLAME .
bulb glows.
ii. And
This shows
metals are
conductor of
electricity
too. hold it over a
now that
to collect
thegood
Magnesium
Oxide
Powder
Watch Glass
Most non-metals produce acidic oxides when dissolve in water
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
i. Take a magnesium ribbon and some sulphur powder, Burn the magnesium ribbon:
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
2Mg(s) + 02(g) -> 2MgO(s)
Take
about
2 cm long magnesium ribbon .
ii. Collect the ashes formed and dissolve them in water.:
Clean +itH20(I)
with sand
paper.
MgO(S)
-> Mg(OH)2(aq)
Hold
thethe
magnesium
ribbon
pair
tongs
start
heating
its
iii. Testing
resultant solution
withwith
bothared
andof
blue
litmus, and
paper,
we find
it is Basic
Mg(OH)2.
other end.
iV. Now burn sulphur
powder.
Place a test
tube over
the burning
sulphur to collect the
The
Magnesium
Ribbon
starts
burning.
fumes produced:
BUT IT'S NOT BURNING ALONE.
S(s) + 02(g) -› SO2(g)
It starts burning with a WHITE DAZZLING FLAME .
v. Add some water to the above test tube and shake:
And now to collect the Magnesium Oxide Powder hold it over a
S02(g) + H20(1) - H2S03 (aq)
Glass
vi. Testing this solution with blue andWatch
red litmus
paper, it is acidic Sulphuric Acid,
H2SO3.
What happens when Metals are burnt in Air
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean
it with
sandMEI
paper.
Chalo Ab
Ise AASAN
BHASHA
Samajhte hai :
Hold
thethe
magnesium
ribbonmetals
with a– pair
of tongs
, and
its
i. Collect
samples of following
aluminium,
copper,
iron,start
lead, heating
magnesium,
zinc and sodium.
other end.
ii. Hold samples with
a pair
of tongs andRibbon
try burning
over burning.
a flame.
The
Magnesium
starts
eg- 2Mg(s) +BUT
02(g)IT'S
-> 2MgO(s).
--We'll getALONE.
metal oxide as product
NOT BURNING
iii. Which metals burn easily- Sodium.
It starts burning with a WHITE DAZZLING FLAME .
iv. What flame colour did you observe when the metal burnt?- Yellow
And now to collect the Magnesium Oxide Powder hold it over a
v. How does the metal surface appear after burning?- Silver white
Watch order
Glassof their reactivity towards oxygenvi. Arrange the metals in the decreasing
Na > Mg > Al > Zn > Fe > Pb > Cu
vii. Are the products soluble in water?- Sodium oxide is soluble in water. Other metal
oxides are insoluble.
viii. We have observed in Activity 3.9 that all metals do not react with oxygen at the
same rate. Different metals show different reactivities towards oxygen
" 10th मतलब ?? - Shobhit Nirwan "
Reaction of metals with Steam
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
A lump of glass wool soaked in water is placed at bottom of tube. The water
Ab
Isesteam
AASAN
BHASHA
in glassChalo
wool will
form
on heating
. MEI Samajhte hai :
about
2 cm
long
magnesium
ribbonkept
. boiling
The SampleTake
of metals
placed
in the
middle
of the horizontally
it with
sand
paper.
tube. The boiling tube Clean
containing
water,
soaked
glass wool and metal sample
arranged
in apparatus.
Holdisthe
magnesium
ribbon with a pair of tongs , and start heating its
To start the experiment, the metal
sample
is heated by using a burner when
other
end.
the metal getsThe
hot,Magnesium
then the glass Ribbon
wool is heated
using other burner.
startsbyburning.
The water present in glass wool forms steam on heating . This steam then
BUT IT'S NOT BURNING ALONE.
passes over the hot metal. The metal react with steam to form the metal oxide
It starts burning with a WHITE DAZZLING FLAME .
and H2 gas.
And
tocome
collect
the
Oxide
Powderover
hold
it over
The now
H2 gas
out of
theMagnesium
boiling tube and
it is collected
water
whenaa
Glass jar, the gas burns with a "pop"
lighted match stick is applied Watch
to gas collected
sound, indicating that it is hydrogen. The metal oxide formed remains behind
in the boiling tube.
This experiment is performed by taking magnesium, aluminium, zinc and iron as
metal sample.
It is found that the reaction of steam with magnesium is most vigorous
followed by reaction with aluminium and zine but reaction with iron is slowest.
Magnesium is very reactive whereas the iron is least reactive.
Decreasing order Mg › Al › Zn > Fe
Metals like lead, silver and gold do not react with water or even steam.
Only those metals displace hydrogen from water which are hydrogen in the
reactivity series.
" 10th मतलब ?? - Shobhit Nirwan "
What happens when Metals react with Acids?
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
i. Which metals reacted vigorously with dilute hydrochloric acid?
Magnesium shows fastest reaction and hydrogen bubble formation.
ii. With which metal did you record the highest temperature?
Magnesium.
iii. Arrange the metals in the decreasing order of reactivity with dilute acids.
Mg > Al > Zn > Fe.
How do Metals react with Solutions of other Metal Salts?
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
i. Put a clean copper wire and put it in a solution of iron sulphate.
ii. Put a clean iron nail in a solution of copper sulphate.
iii. After 20 minutes, it is observed that blue CuSO4 solution turns green.
iv. In which test tube did you find that a reaction has occurred? -- Test tube
containing CuSO4 solution.
v. On what basis can you say that a reaction has actually taken place? -- The blue
colour of CuSO starts fading.
vi. Can you correlate your observations for the Activities 3.9, 3.10 and 3.11? -- Yes.
In those activities, it is found that Iron is more reactive than copper. It displaces
Cu from CuSO4 to form FeS04.
vii. Write a balanced chemical equation for the reaction that has taken place.
Fe(s) + CuSO4(aq) - FeSO4(aq) + Cu(s)
viii.This is a displacement reaction. ie., reactive metals displace less reactive metals
from their compounds in solution or molten form.
" 10th मतलब ?? - Shobhit Nirwan "
CORROSION
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Observations after leaving them for a few days:
i. The iron nails rust in test tube A, but they do not rust in test tubes B and C, because;
ii. In test tube A, the nails are exposed to both air and water.
iii. In test tube B, the nails are exposed to only water.
iv. The nails in test tube C are exposed to dry air.
v. This shows that both air and moisture are needed for rusting of iron.
" 10th मतलब ?? - Shobhit Nirwan "
Ch-4: CARBON
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
The atomic mass of C = 12 u, H = 1 u and O = 16 u.
So, molecular mass of CH3OH = 12 + 3 × 1 + 16 + 1 = 32 u.
The molecular mass of C2H5OH = 12× 2 + 5 × 1 + 16 + 1 = 46 u.
The molecular mass of C3H7OH = 12 × 3 + 7 × 1 + 16 + 1 = 60 u.
And molecular mass of C4H9OH = 12 × 4 + 9 × 1 + 16 + 1 = 74 u.
(a) The difference in the molecular formulae of CH3OH and C2H5OH is CH2. The
difference in the molecular masses of CH3OH and C2H5OH is 46 – 32 = 14 u.
(b) The difference in the molecular formulae of C2H5OH and C3H7OH is CH2. And the
difference in the molecular masses of C2H5OH and C3H7OH is 60 – 46 = 14 u.
(c) The difference in the molecular formulae of C3H7OH and C4H9OH is CH2. And the
difference in the molecular masses of C3H7OH and C4H9OH is 74 – 60 = 14 u.
(i) Yes, there is a similarity in the difference between their molecular formulae and
molecular masses. Their molecular formulae differ by CH2 (1 carbon atom and 2
hydrogen atoms), and their molecular masses differ by 14 u.
(ii) These alcohols can be arranged in the order of the increasing carbon atoms as
follows : CH3OH, C2H5OH, C3H7OH, C4H9OH
Yes, we can call it a homologous series.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
NOTE: Saturated hydrocarbons will generally give a clean flame while unsaturated
carbon compounds will give a yellow flame with lots of black smoke. Now,
• Camphor & Naphthalene are unsaturated hydrocarbons. So they burn with yellow
flame and leave residues.
• Alcohol is saturated and burns with clean blue flame.
This results in a sooty deposit on the metal plate
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Limiting the supply of air results in incomplete combustion of even saturated
hydrocarbons giving a sooty flame
When do you get a flame? - In presence of a sufficient supply of air with oxygen, it
gives a blue flame.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
i. When KMnO4 is added, its purple colour disappears initially.
ii. Why does the colour of potassium permanganate not disappear when excess
is added? -- Because all the alcohol gets consumed and the reaction stops.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
i. We observed a product (Sodium ethoxide) with hydrogen gas.
ii. How will you test the gas evolved? -- When a burning spitter is brought near to the
gas, the gas burns with pop sound.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
This is esterification reaction,
Product obtained is ester, having sweet smell.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Foam is formed with difficulty and an insoluble substance (scum) remains after washing
with water. This is caused by the reaction of soap with the calcium and magnesium
salts, which cause the hardness of water. Hence you need to use a larger amount of
soap. This problem is overcome by using another class of compounds called detergents
as cleansing agents.
In which test tube do you get more foam?- Distilled water test tube.
In which test tube do you observe a white curdy precipitate?- Hard water test
tube.
Do both test tubes have the same amount of foam?- No. The test tube containing
detergent has more foam.
In which test tube is a curdy solid formed? -- In the test tube containing soap.
" 10th मतलब ?? - Shobhit Nirwan "
Ch-5: Life Processes
Activity to demonstrate that Chlorophyll is necessary for
Photosynthesis
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take a potted plant with variegated leaves – for example, money plant or
crotons.
Keep the plant in a dark room for three days so that all the starch gets used
up.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Now keep the
plant
in sunlight
forlong
about
six hours.
Take
about
2 cm
magnesium
ribbon .
Pluck a leaf from the plant.
Mark
the
green
areas
in
it
Clean it with sand paper. and trace them on a
sheet of paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
Dip the leaf in boiling water for a few minutes.
other end.
After this, immerse it in a beaker containing alcohol.
The
startsand
burning.
Carefully place
theMagnesium
above beaker Ribbon
in a water-bath
heat till the alcohol
BUT
IT'S
NOT
BURNING
ALONE.
begins to boil.
It the
starts
a WHITE
FLAME .
Now dip
leaf burning
in a dilute with
solution
of iodineDAZZLING
for a few minutes.
Takenow
out the
and rinse
the iodine solution.
And
to leaf
collect
the off
Magnesium
Oxide Powder hold it over a
Observe the colour of the leafWatch
and compare
Glassthis with the tracing of the leaf
done in the beginning .
Question 1. What happens to the colour of the leaf? What is the colour of the
solution?
Answer. The green leaf becomes colourless. On immersing green leaf in a alcohol,
chlorophyll responsible for its green colour gets dissolves in alcohol. The colour of
the alcohol solution turns green
Question 2. What can you conclude about the presence of starch in various
areas of the leaf?
Answer. The green areas of leaf, which turns dark blue on dipping in iodine
solution, indicate the presence of starch where as colorless part of leaf show no
formation of starch. From this activity we can conclude that chlorophyll is essential
for photosynthesis
" 10th मतलब ?? - Shobhit Nirwan "
Activity to show that amount of Carbon Dioxide (CO2), essentially
affects the process and outcome of Photosynthesis
ChaloChalo
Ab Ise
AASAN
MEI
Samajhte
Ab Ise
AASANBHASHA
BHASHA MEI
Samajhte
hai : hai :
Take potted
aboutplants
2 cmwhich
long are
magnesium
ribbon
Take two healthy
nearly the same
size..
Keep them in a dark room
for it
three
days.
Clean
with
sand paper.
Now
place
each
plant
on
separate
glass
Place,aand
watch-glass
Hold the magnesium ribbon with a pairplates.
of tongs
start heating its
containing potassium hydroxide by the side of one of the plants. The
other end.
potassium hydroxide is used to absorb carbon dioxide.
The Magnesium Ribbon starts burning.
Cover both plants with separate bell-jars as shown in Fig. .
BUT IT'S NOT BURNING ALONE.
Use Vaseline to seal the bottom of the jars to the glass plates so that the setIt starts burning with a WHITE DAZZLING FLAME .
up is air-tight.
And
now
collect
the Magnesium
Oxide Powder hold it over a
Keep
the to
plants
in sunlight
for about two hours.
Pluck a leaf from each plant and
check
for the presence of starch as in the
Watch
Glass
above activity.
Question 1. Do both the leaves show the presence of the same amount of
starch?
Answer. No, both the leaves do not show the presence of the same amount of
starch, because in photosynthesis starch is produced using sun light, chlorophyll
and CO2. In first set up availability of CO2 will be less for making starch by the
plant leaves, as potassium hydroxide (KOH ) absorb the CO2. In second plant
setup, the leaves will have more amount of starch.
Question 2. What can you conclude from this activity?
Answer. From this activity, we can conclude that amount of Carbon Dioxide (CO2)
, essentially affects the process and outcome of photosynthesis.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other
end.MEI Samajhte hai :
Chalo Ab Ise AASAN
BHASHA
Thesolution
Magnesium
Ribbon
starts
burning.
Take 1 mL starch
(1%) in two
test tubes
(A and
B).
IT'S ANOT
BURNING
ALONE.
Add 1 mL saliva toBUT
test tube
and leave
both test
tubes undisturbed for 20-30
minutes.
It starts burning with a WHITE DAZZLING FLAME .
Nownow
add a
drops of
dilute
iodine solution
to the
test tubes.
And
tofew
collect
the
Magnesium
Oxide
Powder
hold it over a
Question 1. In which test tube doWatch
you observe
a
colour
change?
Glass
Answer. We will observe a colour change in test tube B, showing presence of
starch. Where as test tube A will show no colour change as due to addition of
saliva, starch is converted into sugar.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
other
end.
Take some freshly prepared lime
water
in a test tube.
The this
Magnesium
Blow air through
lime water. Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
QuestionIt1.starts
Note how
long it with
takesafor
the lime
water to turn
milky?.
burning
WHITE
DAZZLING
FLAME
Answer.
When
blow air
through
mouth, theOxide
lime water
in testhold
tube it
turns
milky
And now
towe
collect
the
Magnesium
Powder
over
a
within no time. Use a syringe or pichkari
to
pass
air
through
some
fresh
lime
water
Watch Glass
taken in another test tube.
Question 2. Note how long it takes for this lime water to turn milky?
Answer. When we use syringe or pichkari, to pass air through the lime solution, it
takes much time and effort to turn the lime water milky.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean
it with
sand MEI
paper.
Chalo Ab
Ise AASAN
BHASHA
Samajhte hai :
Hold the
ribbon
with
a pair
tongs
and to
start
Takemagnesium
some fruit juice
or sugar
solution
andof
add
some ,yeast
this. heating
Take this its
mixture in a test tube fitted with
a one-holed
other
end. cork.
Fit the cork The
with aMagnesium
bent glass tube.
Dip thestarts
free end
of the glass tube into a
Ribbon
burning.
test tube containing
prepared
lime water.
BUTfreshly
IT'S NOT
BURNING
ALONE.
It starts burning with a WHITE DAZZLING FLAME .
Question 1. What change is observed in the lime water and how long does it
And now to collect the Magnesium Oxide Powder hold it over a
take for this change to occur?
Answer. The lime water becomesWatch
milky asGlass
carbon dioxide is produced by mixing
yeast in sugar along with alcohol. Time taken for this change to occur, should be
observed by students themselves.
Question 2. What does this tell us about the products of fermentation?
Answer.The products of fermentation are alcohol and carbon dioxide.
" 10th मतलब ?? - Shobhit Nirwan "
Ch-6: Control & Coordination
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT
NOT
ALONE.
Have the old parts of
the IT'S
shoot
and BURNING
root changed
direction?
It starts
with
a WHITE
FLAME
Answer: The
old partsburning
of the shoot
and
root haveDAZZLING
no noticeable
change. in
direction.
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
Are there differences in the direction of the new growth?
Answer: New growth parts show change in direction. i.e., shoot bends towards
light and roots bend away from it.
What can we conclude from this activity?
Answer: Shoots show phototropism and the roots show geotropism.
" 10th मतलब ?? - Shobhit Nirwan "
Ch-7: Reproduction
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Activity Observation: Under
the it
microscope,
see yeast reproducing by
Clean
with sandwepaper.
forming
Hold
thebuds.
magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning
a WHITE
DAZZLING
FLAMEof. moist
Activity Observation:
A whitewith
cottony
mass appears
on the surface
bread
black within
few days. The white
cottony
masshold
is dueittoover
growth
Andwhich
now turns
to collect
the Magnesium
Oxide
Powder
a
of bread mould (Rhizopus). The spores
of fungus
Watch
Glassare present in the air. They settle
on the moist bread and germinate to form white cottony mass of vegetative
mycelium. The vegetative mycelium develops asexual sporangia which are black in
colour. Each sporangium contains hundreds of minute black- coloured spores.
These spores are dispersed in air to germinate on suitable substratum
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Activity Observation: Spirogyra, simply breaks up into smaller pieces upon
Clean it with sand paper.
maturation. These pieces or fragments grow into new individuals
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
" 10th मतलब ?? - Shobhit Nirwan "
Activity Observation: The potato pieces having buds gradually grows and
develops. But there is no growth and development in potato pieces without buds.
Which are the potato pieces that give rise to fresh green shoots and roots?
The pieces with buds give rise to fresh green shoots and roots.
Activity Observation: Portion of Money plant with at least one leaf grows and
gives rise to fresh leaves. But money plant without leaf dies.
What can you conclude from your observations?
Money plant with green leaves can synthesize food through photosynthesis and
able to grow into a plant, through vegetative propagation.
Activity Observation: Two seed cotyledons are separated by radicle and plumule
formation.
" 10th मतलब ?? - Shobhit Nirwan "
Ch-9- Light: Reflection & Refraction
Chalo
AbAb
Ise
BHASHA
Samajhte
Chalo
IseAASAN
AASAN BHASHA
MEIMEI
Samajhte
hai : hai :
Take of
about
2 cm
longcould
magnesium
ribbon
.
The curved surface
a shining
spoon
be considered
as a curved
mirror.
One Convex surface and
other it
concave
surface.
Sp for answering the
Clean
with sand
paper.
questions
keep in mindribbon
the properties
bothof
thetongs
spherical
mirrors.
Hold
the magnesium
with aofpair
, and
start heating its
Question 1: Do you get the image?other
Is it smaller
end. or larger?
Yes. The image on the outer curved surface is smaller.
The Magnesium Ribbon starts burning.
Question 2: Move the spoon slowly away from your face. Observe the image.
BUT IT'S NOT BURNING ALONE.
How does it change?
It starts
burningdecreases.
with a WHITE DAZZLING FLAME .
The size of the
image gradually
And now
to collect
the Magnesium
Oxide
Powder
it over a
Question
3: n Reverse
the spoon
and repeat the
Activity.
How hold
does the
image look like now?
Watch Glass
The image at its concave side is real, inverted and diminished.
Question 4: Compare the characteristics of the image on the two surfaces.
• The image at its concave side is real, inverted and diminished. If the spoon is
moved away, the image becomes smaller.
• Image at the convex side is virtual, erect & diminished. If the spoon is moved
away, the image becomes smaller.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
Chalo Ab Ise AASAN
BHASHA
other
end.MEI Samajhte hai :
The paper atThe
first begins
to burn producing
smoke. burning.
Eventually it may even
Magnesium
Ribbon starts
catch fire.
BUT IT'S NOT BURNING ALONE.
Why does it burn? The light from the Sun is converged at a point, as a sharp,
It starts burning with a WHITE DAZZLING FLAME .
bright spot by the mirror. In fact, this spot of light is the image of the Sun on
And
the
Magnesium
Powder
hold it over a
the now
sheetto
of collect
paper. This
point
is the focus Oxide
of the concave
mirror.
Glass of sunlight ignites the paper. The
The heat produced due to theWatch
concentration
distance of this image from the position of the mirror gives the approximate
value of focal length of the mirror
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other
end.MEI Samajhte hai :
Chalo Ab Ise AASAN
BHASHA
This activity isThe
basically
to find outRibbon
the positions
of the
image formed by the
Magnesium
starts
burning.
concave mirrors, their
size etc.
BUTnature,
IT'S NOT
BURNING ALONE.
You will
see
in
the
above
Activity
that
the nature,
position FLAME
and size of
It starts burning with a WHITE
DAZZLING
. the
image formed by a concave mirror depends on the position of the object in
And now to collect the Magnesium Oxide Powder hold it over a
relation to points P, F and C.
Watch Glass
The image formed is real for some positions, nd virtual for other.
The image is either magnified, reduced or has the same size, depending on
the position of the object.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
This activity is basically to find out the positions of the image formed by the
Take about 2 cm long magnesium ribbon .
convex mirrors, their nature, size etc.
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
Question 1: Observe the image of the pencil in the mirror. Is the image erect
And now to collect the Magnesium Oxide Powder hold it over a
or inverted? Is it diminished or enlarged?
Watch Glass
Its image in the mirror is erect and diminished.
Question 2: Move the pencil away from the mirror slowly. Does the image
become smaller or larger?
The image becomes smaller.
Question 3: Repeat this Activity carefully. State whether the image will move
closer to or farther away from the focus as the object is moved away from
the mirror?
The image moves closer to the focus.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
Chalo Ab Ise AASAN
BHASHA
other
end.MEI Samajhte hai :
This activity isThe
basically
to find outRibbon
which of starts
these mirrors
will give the full
Magnesium
burning.
image of a large BUT
object?
IT'S NOT BURNING ALONE.
Observation: You can see a full-length image of a tall building/tree in a
It starts burning with a WHITE DAZZLING FLAME .
small convex mirror. One such mirror is fitted in a wall of Agra Fort facing Taj
And now to collect the Magnesium Oxide Powder hold it over a
Mahal.
Watch Glass
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Chalo
Ab Ise 2AASAN
BHASHA
MEI Samajhte
hai : .
Take
about
cm long
magnesium
ribbon
These activities are toClean
understand
the sand
phenomenon
it with
paper.of refraction of light.
Light does not travel in the same direction in all media. It appears that when
Hold the magnesium ribbon with a pair of tongs , and start heating its
travelling obliquely from one medium to another, the direction of propagation
other end.
of light in the second medium changes.
The Magnesium Ribbon starts burning.
BUT
NOTabove
BURNING
Question 1: With your
eye IT'S
to a side
water,ALONE.
try to pick up the coin in one
It succeed
starts burning
with
a WHITE
go. Did you
in picking
up the
coin? DAZZLING FLAME .
NoAnd now to collect the Magnesium Oxide Powder hold it over a
Question 2: Repeat the Activity.Watch
Why didGlass
you not succeed in doing it in one
go?
Reflected light coming from the submerged coin in water (denser medium), on
entering air (rarer medium), bend away from the normal due to refraction of light
and image size becomes larger than its actual size. Thus, coin appears to be
closer than its actual distance.
Question 3: Keep looking for the coin from your position. Does the coin
becomes visible again from your position? How could this happen?
Yes. The coin becomes visible again. This is because the coin appears slightly
raised above its actual point due to refraction of light.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Draw a thick straight line in ink, over a sheet of white paper on a table.
Place a glass slab over the line in such a way that one of its edges makes an
angle with the line.
Question: Look at the portion of the line under the slab from the sides.
Chalo
Ab Ise AASAN
Samajhte
hai : to be
What do
you observe?
Does theBHASHA
line underMEI
the glass
slab appear
bent at theTake
edges?
-- Yes,
the line
under
the slab appears
to be
about
2 cm
long
magnesium
ribbon
. bent and it
is due to refraction. Clean it with sand paper.
Next, place the glass slab such that it is normal to the line.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Question: What do you observe
now?
Does the part of the line under the
Watch
Glass
glass slab appear bent? -- No, the part of the line under the glass slab does
not appear bent because the ray of light is perpendicular to the slab and does
not make any angle, so it appears straight.
OBSERVATION: This activity demonstrates the phenomenon of refraction and
for normal incidence, there no refraction occurs.
Question: Look at the line from the top of the glass slab. Does the part of
the line beneath the slab, appear to be raised? why does this happen? -Yes, the part of the line beneath the slab appears to be raised because of
refraction.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
And now to collect the Magnesium Oxide Powder hold it over a
Watch Glass
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
These activities
areMagnesium
to understandRibbon
the phenomenon
of refraction of light
The
starts burning.
through glass slab.
BUT IT'S NOT BURNING ALONE.
Here, the light ray has changed its direction at points O and O'. Both the
It starts burning with a WHITE DAZZLING FLAME .
points O and O' lie on
And
to at
collect
Magnesium
over a
The now
light ray
point Othe
enters
from a rarerOxide
mediumPowder
(air) to ahold
denseritmedium
Watch Glass
(glass). The light ray
Compare the angle of incidence with angle of refraction at both refracting
surfaces AB & CD. A ray EO is obliquely incident on surface AB, called
incident ray.
OO′ is the refracted ray and O′ H is the emergent ray. You may observe that
the emergent ray is parallel to the direction of the incident ray.
Why does it happen so? The
However, the light ray is shifted sideward slightly.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other
end.MEI Samajhte hai :
Chalo Ab Ise AASAN
BHASHA
The to
Magnesium
Ribbon
burning.
The paper begins
burn producing
smoke.starts
It may even
catch fire after a
while.
BUT IT'S NOT BURNING ALONE.
Why does
this happen?
The with
light from
the Sun
constitutes parallel
It starts
burning
a WHITE
DAZZLING
FLAMErays
. of light.
These
raysto
were
converged
by the lens at the
sharp
bright spot
formed
on the
And
now
collect
the Magnesium
Oxide
Powder
hold
it over
a
paper. In fact, the bright spot you got on the paper is a real image of the Sun.
Watch Glass
The concentration of the sunlight at a point generated heat. This caused the
paper to burn.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
This activity is basically to find out the positions of the image formed by the
convex lens, their nature, size etc.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
This activity is basically to find out the positions of the image formed by the
concave lens, their nature, size etc.
" 10th मतलब ?? - Shobhit Nirwan "
Ch-12- Electricity
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Chalo AbClean
Ise AASAN
BHASHA
Samajhte hai :
it with
sandMEI
paper.
This activity is basically for obtaining V-I graph (Ohm's Law).
Hold the magnesium ribbon with a pair of tongs , and start heating its
First, only one cell is the voltage source, note down the ammeter and
other end.
voltmeter readings and fill in the table provided.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
It starts burning with a WHITE DAZZLING FLAME .
i1
v1
v1/i1
And now to collect the Magnesium
Oxide
Powder
hold it over a
i2
v2
v2/i2
i3Watch Glassv3
v3/i3
i4
v4
v4/i4
We observed that approximately the same value for V/I is obtained in each
case. Thus the V–I graph is a straight line that passes through the origin of the
graph, as shown in Fig. 12.3. Thus, V/I is a constant ratio.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
BUT IT'S
NOT
BURNING
This activity is basically
to study
about
electricalALONE.
resistance of a conductor.
It
starts
burning
with
a
WHITE
DAZZLING
FLAME .
In this Activity we observe that the current is different for different
And
to differ?
collect
the Magnesium
Oxide
Powder
hold
over
Whynow
do they
Certain
components offer
an easy
path for
theitflow
of a
electrical current while the others
resistGlass
the flow.
Watch
We know that the motion of electrons in an electric circuit constitutes an
electric current. The electrons, however are not completely free to move within
a conductor. They are restrained by the attraction of the atoms among which
they move.
Thus, motion of electrons through a conductor is retarded by its resistance.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
This activity is basically to find out factors on which resistance of a conductor
depends.
We know,
Answering the questions keeping in mind this only.
Question: Does the current depend on the length of the conductor? - Yes
Question: Does the current depend on the area of cross-section of the wire
used? - Yes
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
This activity is basically to understand that the current in the ammeter is the
same, independent of its position in the electric circuit.
It means that in a series combination of resistors the current is the same in
every part of the circuit or the same current through each resistor.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
This activity is basically to understand that the potential difference V is equal
to the sum of potential differences V1 , V2 , and V3 .
That is the total potential difference across a combination of resistors in series
is equal to the sum of potential difference across the individual resistors.
V = V1 + V2 + V3
*Activity 12.6 is derivation of equivalent resistance formula for parallel.
" 10th मतलब ?? - Shobhit Nirwan "
Ch-13- Magnetic Effects
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
BUT IT'S NOT BURNING ALONE.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
It starts burning with a WHITE DAZZLING FLAME .
We see that the needle is deflected which means that the electric current through
And
nowwire
to has
collect
the Magnesium
Oxide
hold
over a
the
copper
produced
a magnetic effect.
ThusPowder
we can say
thatitelectricity
and magnetism are linked to eachWatch
other Glass
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
Take about 2 cm long magnesium ribbon .
Clean it with sand paper.
Hold the magnesium ribbon with a pair of tongs , and start heating its
other end.
The Magnesium Ribbon starts burning.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
BUT IT'S NOT BURNING ALONE.
The magnet exerts its influence in the region surrounding it. Therefore the iron
It starts
burning
with thus
a WHITE
FLAME
.
filings experience
a force.
The force
exertedDAZZLING
makes iron filings
to arrange
in a
And now to collect
the
Magnesium
OxideinPowder
pattern(Fig-13.2).
The region
surrounding
a magnet,
which thehold
force it
of over
the a
Watch
magnet can be detected, is said to
have aGlass
magnetic field. The lines along which
the iron filings align themselves represent magnetic field lines.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
We shall first consider the pattern of the magnetic field around a straight conductor
carrying current.
What happens to the deflection of the compass needle placed at a given point if the
current in the copper wire is changed? To see this, vary the current in the wire. We find
that the deflection in the needle also changes. In fact, if the current is increased, the
deflection also increases. It indicates that the magnitude of the magnetic field produced
at a given point increases as the current through the wire increases.
What happens to the deflection of the needle if the compass is moved away from
the copper wire but the current through the wire remains the same? To see this, now
place the compass at a farther point from the conducting wire (say at point Q).
What change do you observe? We see that the deflection in the needle decreases. Thus
the magnetic field produced by a given current in the conductor decreases as the
distance from it increases.
From Fig. 13.6, it can be noticed that the concentric circles representing the magnetic field
around a current-carrying straight wire become larger and larger as we move away from
it.
Does the direction of magnetic field lines get reversed if the direction of current
through the straight copper wire is reversed? -- The direction of magnetic field lines is
reversed if the direction of current through the copper wire is reversed.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
The displacement of the rod (AB) suggests that:
A force is exerted on the current-carrying aluminium rod when it is placed in a
magnetic field.
The direction of force is also reversed when the direction of current through the
conductor is reversed.
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
If the south pole of the magnet is moved towards the end B, the deflections in the
galvanometer would just be opposite to the previous case.
When the coil & magnet are stationary, there is no deflection in the galvanometer.
This activity shows that the motion of a magnet with respect to the coil produces an
induced potential difference, which sets up an induced electric current in the circuit.
" 10th मतलब ?? - Shobhit Nirwan "
Chalo Ab Ise AASAN BHASHA MEI Samajhte hai :
As soon as the current in coil-1 reaches either a steady value or zero, the
galvanometer in coil-2 shows no deflection.
We conclude that a potential difference is induced in coil-2 whenever the electric
current through the coil-1 is changing (starting or stopping). Coil-1 is called the
primary coil and coil-2 is called the secondary coil. As the current in the first coil
changes, the magnetic field associated with it also changes. Thus the magnetic field
lines around the secondary coil also change. Hence the change in magnetic field
lines associated with the secondary coil is the cause of induced electric current in it.
This process, by which a changing magnetic field in a conductor induces a current in
another conductor, is called electromagnetic induction
" 10th मतलब ?? - Shobhit Nirwan "