1. Write the difference between kinetic and potential energy.
Ans. Kinetic energy is the energy an objects has when it is moving, potential energy is
the energy an object has because of its position.
Activity: Activity 8.1 and 8.2(Simple Pendulum apparatus required to perform) and bouncy balls.
2. The diagram shows a simple pendulum.
Complete the sentences:
a.At B, the pendulum has _____minimum__________ kinetic energy and
__maximum_____________ potential energy.
At O, the pendulum has _____maximum__________ kinetic energy and
___minimum____________ potential energy.
At D, the pendulum has kinetic and potential energy that are ___equal____________.
b. Complete the equation for the pendulum using the mathematical symbols from the list.
Choose the best symbols from the list.
+ ,
-
,
x
,
=
, ÷
Kinetic energy _____+________ potential energy ______=______________ constant.
3. Explain the principle of conservation of energy.
ans. The law of conservation of energy states that energy an neither be created nor
destroyed it can only be transferred from one from to another this says that energy is
always dissipated not destroyed
4. A refrigerator works by using energy from an electrical supply to reduce the temperature
inside the storage compartment.
Use the principle of conservation of energy to explain why the temperature outside the
refrigerator must increase.
Ans. As the law states energy cannot be created nor can it be destroyed it is transferred
from one from to another therefore the waste energy is transformed as heat.
5. Explain energy dissipation by giving an example from day to day life.
Ans. Energy dissipation is when energy is lost to the environment, bulb
6. Activity 8.2 Student’s Textbook.
Requirement: bouncy ball, meter scale.
Complete the sentences:
Thermal energy is the total amount _____of temperature in an
object__________________________________.
Temperature is the ___________________measure of cold or
hot_________________________________.
The quantity (thermal energy or temperature) that can be measured directly is
__________________.
You can measure temperature by ____thermometer__________ and its S.I unit is
______degree Celsius __________.
When two objects at different temperatures come into contact, thermal energy flows from
the ________hotter______ object to the ___cooler____________object until they are at
same temperature.
7. Does thermal energy move from hot objects to cooler objects or from cool objects to
hotter objects, explain why?
It moves from hotter objects to cooler objects to balance their temperature
8. Which has the most thermal energy, a litre of water at 30 degrees celsius or 200cm3 of
water at the same temperature? explain your answer
200cm cube of water because it has more volume therefore the thermal energy is more
9. Jo lives in a country that has very cold winters. Jo says that it is important to make sure
that all the windows in her house have very thick curtains to stop the cold from coming
in. explain why, what jo has said is not correct.
10. Why does putting your hand in hot water burn your hand but cool water doesnt?Why
shouldnt you put hot objects into a fridge
11. It was once believed that objects that were warm contained more of a substance called
‘caloric’ value than substances that were cooler.
a.Name one famous scientist whose work helped to replace the ‘caloric’ theory?
b. Give one piece of evidence that suggested that ‘caloric’ theory was wrong.
12. 1 kilojoules = 1000 joules
1
1
Joule = 1000000 mega joules
An electric kettle uses 1.5 kilojoules of energy every second.
a.How many joules of energy does it use every second?
b.How many kilojoules of energy would the kettle use if it was used for 20 min.?
c.How many mega joules of energy is your answer to b part?
d. Why is it more sensible to write your answer to b as kilojoules or mega joules
rather than as joules?
e. Write the symbols for kilojoules and mega joules.
13. Activity on heat dissipation using blue and pink ink, warm and cold water.
Mix blue food colouring with cold water to represent a cold region of a substance. Add a few
drops of red food colouring to hot water to represent a hot region. Gently pour the red, warm
water on top of the blue, cold water. Over time, the red coloured water will spread throughout
the entire body of water, changing the colour of the colder water.
1. 1Practice Diagram Bohr Model of an atom.
4
.
Hydrogen is the simplest atom.
a) It has only -------1--- electron.
b) How many electron shells does a hydrogen atom have?--1-c) What is this shell called? -k----d) Is this shell complete? ......no...
2. Draw Bohr’s model of Sulphur atom.
a)
b)
c)
d)
e)
How many protons and neutrons does Sulphur have?
How many electrons does sulphur have? ..16........
How many electrons shells does sulphur have? .......3...
What is the first shell called? .....k.....
How many electron does this shell have?...2......
f) What is the second shell called? ..l........
g) How many electrons does this shell have?...8......
h) What is the third shell called? .......m...
i) How many electron shells this shell have?.....6....
j) Is this shell full? …no…..
3. Why do scientists use models?
4. Name the three subatomic particles of an atom.
Ans. Proton, neutron and electron
5. Define atomic mass and atomic number.
Ans. Atomic mass is the total of the number of protons and
neutrons while atomic number is how many electrons it has
6. Why does a hydrogen atom not have a neutron?
Its nucleus is not big enough to have a nucleus.
7. Name the scientist who discovered :
a.proton ernest rutherford
b.electron jj thomson
c.neutron james chadwick
8. The diagram shows the model of a carbon atom.
https://useruploads.socratic.org/ACLqQS2jRaeBWW1o2DaP_Atom-model-carbon-Unitoday-400x333.jpg
Use the diagram to explain where carbon is found in the Periodic Table.
3,6
9. The diagram shows the model of a magnesium atom.
https://useruploads.socratic.org/t68GzkplTEGJNEJPz7JT_Magnesium.jpg
Use the diagram to explain where magnesium is found in the Periodic Table.
3,12
10. Draw a diagram to show the structure of the potassium atom and explain how it relates to
its position in the Periodic Table.
11. The diagram shows an image of Rutherford’s model of the atom.
https://images.app.goo.gl/rRnaxXVskP4EwyDG7
a. Compare Rutherford’s model of the atom with the one we use today.
Ans. The electrons have no shells and are floating around. the nucleus has only
protons
b. Explain why Rutherford’s model of the atom is no longer used by scientists today.
Q1. a)What is voltage? Write its S.I unit. Voltage is the measure of the energy in a circuit, si unit
volts
b) Define electric current. Name the device used to measure it. ammeter
Q2. Draw the conventional symbols for the components of an electric circuit.
Q3. Why do scientists use electric circuit models?
Q4. Draw a circuit diagram for a bulb connected to a cell with a switch. Mark arrow in the
diagram to indicate the direction of flow of current.
Q5.a.What is the maximum output voltage of four 1.5V cells connected together?
Ans. 1.5v
b. What would happen to the output voltage if one of the four cells were connected
the wrong way
round?
Ans. They wont work
Q6.What is resistance?
A measure of how difficult it is for current to flow
Q7:What does Ohm's law states?
The current from one point to another is directly proportional to the voltage across
one point to another
Q8: What is a Variable Resistor? Explain its different types.
A variable resistor is a resistor whose resistance can be varied, there are 2 types Light dependent resistor- whose resistance varies depending on the light-level.
 Thermal resistor- whose resistance varies depending on the temperature.
Q9: On what factors does the resistance of a conductor depend?
The conductor’s resistance has 3 main factors


Thickness of the conductor
Conductivity of the metal
Reactivity of the metal
Q10. Complete the sentences below:
The resistance of a circuit measures how difficult it is for current to flow.
The bigger the resistance, the more energy or current is needed to make a current flow.
Resistance is measured in units called ohms whose symbol is the Greek letter Ω.
Q11. A 2V cell is connected to a 10Ω resistor. What current flows in the resistor?
0.2
Q12. A 6V cell is connected to a 20Ω resistor. What current flows in the resistor?
0.3
Q13. What voltage is needed to make a current of 0.2A flow through a 40Ω resistor?
Q14. If the resistance of an electric iron is 50Ω and a current of 3.2A flows through the
resistance. Find the voltage between two points.
3.2v
Q15. A current of 0.5A flows through a resistor when a voltage of 24V is applied. What is the
resistance of the resistor?
12Ω
Q16. a)A voltmeter is needed to measure the voltage across a lamp in an electric circuit. It
must be connected in parallel with the lamp.
b) An Ammeter is needed to measure the current through a lamp in an electric circuit. It must
be connected in series with the lamp.
Q17. A child has drawn the electric circuit to study Ohm’s law as shown in following figure. His
teacher told that the circuit diagram needs correction. Study the circuit diagram and redraw it after
making all corrections. Give reasons for the correction you made.
The ammeter is in parallel while it should be in series and the voltmeter is connected in series
while it should be in parallel
Q1. Rohan and Nishant were working on the types of circuits and drew them in the notebook but
they got confused which circuit is in series and parallel. Draw the types of circuits and explain
them.
Q2. Naina’s friend made a simple electric circuit as their school project but she wants to measure
the current so she asked Naina for the help and the way by which she can measure the current
flowing in the circuit. According to you what Naina might have suggested her and in what way
her suggestion was helpful to her.
She must have suggested her to use an ammeter and it would be helpful in measuring the current
Q3. Draw the circuits for the following investigations or uses:
a.Two lamps in parallel with a cell and one switch that controls both lamps.
b. Three cells in series with a resistor and a switch.
QUICK REVIEW (oral).
True or False.
a)
b)
c)
d)
e)
f)
A lamp/bulb will glow in an incomplete electric circuit.
An Ammeter is always connected in Series in all the circuits.
A Series circuit has just one current loop.
A Parallel circuit consists of two or more current loops.
Electric current is measured in Joules.
Choose the correct words that match the given statements from the list given below:
Current, Voltmeter, conductor, Ammeter, variable resistance, diode, insulator, battery, reed
switch
a)
b)
c)
d)
e)
A device for measuring current.
Rate of flow of electric charge carried by electrons.
More than one cell connected in series.
A material that allows the electric current to pass through it.
A switch that can be operated by a magnet.
f) A device that allows the current to flow through it in one direction.
g) A resistor that is used to vary the current in a circuit.
Q4. The table below contains statements about Series and Parallel circuits. Complete the table by
writing either series or parallel next to each statement.
Q5. The diagram below shows the model for electric current.
a) In the model above, what do the towns represent?
b) In the model above, what does the warehouse represent?
c) Can you adapt this model to explain what happens to current in a Parallel Circuit?
Q6.
Student’s Textbook:
Activity 10.4, 10.5, 10.6 ( The given activities include making of series and parallel circuits to
hypothesize the flow of current and measure it)
In the central heating model, what would represent:
a. Voltage
b. Current
c. Resistance
Household lights are connected in a parallel circuit. Explain why this is better than a series
circuit?
Draw a diagram for a circuit with two lamps and two switches arranged so that the lamps can be
controlled separately
A cell in a parallel circuit can light two lamps as brightly as one lamp on its own. Sajid says that
this will save him money on buying cells. Explain why he is wrong.