K.K. AGRAWAL
SYMBOLS USED IN PHYSICS
a
acceleration (m/s2)
A
Amplitude (m), Ampere (fundamental unit of current)
b
y-intercept
B
magnetic field strength (T = 104 G), Bulk Modulus (N/m2)
c
speed of light (3 x 108 m/s), specific heat (J/(kg•K))
C
Coulomb (unit of charge = A•s), center of curvature (m), Celcius (unit of Temperature),
Capacitance (F)
cal
calories (unit of heat energy = 4.186 J)
d
distance (m), deci (prefix = 10-1)
dB
decibels (unit of sound intensity)
e
symbol for charge of an electron (1.6 x 10-19), efficiency (dimensionless)
eV
electron-Volt (unit of energy = 1.6 x10-19 J)
E
energy (J), electric field intensity (N/C)
f
frequency (Hz = s-1), femto (prefix = 10-15), force of friction, focal length (m), final
value(subscript)
F
force (N), farad (unit of capacitance = A2•s4/(kg•m2), Fahrenheit (unit of Temperature)
g
acceleration due to gravity (9.8 m/s2), gram (unit of mass)
G
Giga (prefix = 109) Universal Gravitational Constant (6.67 x 10-11 m3/(kg•s2)
h
Planck’s constant (6.626 x 10-34 J•s), height (m)
H
Henry (unit of inductance)
Hz
Hertz (unit of frequency)
i
current (A), initial value (subscript)
I
moment of inertia (kg•m2), Luminous Intensity (W/m2)
J
Joule (unit of energy / work), impulse (N•s)
k
kilo (prefix = 103)spring constant (N/m = kg/s2), thermal conductivity (W/(m•K)), Boltzman
constant (J/K)
kg
kilogram (fundamental unit of mass)
K
Kelvin (fundamental unit of temperature), kinetic energy (J)
1
K.K. AGRAWAL
l
length (m)
L
liter (unit of volume), latent heat (J/kg), angular momentum (J•s), inductance (H), latent heat
(J/kg)
m
mass (kg), meter (fundamental unit of distance), slope, milli (prefix = 10-3)
M
mega (prefix = 106)
n
nano (prefix = 10-9), index of refraction (dimensionless), number of moles
N
Newton (unit of force), Normal Force (N), number of particles
NA
Avogadro’s number (6.022 x 1023 particles / mole)
o
subscript - initial
p
momentum (N•s), pico (prefix = 10-12), proton
P
power (W), pressure (N/m2, atm, mmHg, psi, Pa)
Pa
Pascals (unit of pressure = N/m2)
q
charge (C)
Q
charge (C), Heat (J)
r
radius (m)
R
ideal gas constant (8.31 J/mol K), resistance (Ω)
rms
root – mean – square
s
seconds (fundamental unit of time)
S
entropy (J/K)
t
time (s)
T
temperature (°C, K), period (s), tension (F), Tesla (unit of magnetic field)
u
atomic mass unit (also amu, 1.6 x10-27 kg)
U
potential energy (J)
v
velocity or speed (m/s)
V
Volt (unit of potential difference), Voltage or Potential Difference, volume (L or m3)
w
weight (N), W- work (J), Watt (unit of power)
x
distance – usually horizontal
X
reactance – capacitive or inductive (Ω)
2
K.K. AGRAWAL
y
distance – usually vertical
Y
Young’s Modulus (N/m2)
z
distance – usually 3rd dimension
Z
impedance (Ω)
GREEK LETTERS
α (alpha) - angular velocity (rad/s2), proportional symbol, temperature coefficient of linear expansion
(K-1), α – type of radiation
β (beta) – temperature of area expansion (K-1), type of radiation, electron
γ(gamma) – relativistic gamma factor (dimensionless), type of radiation
δ (delta)– instantaneous change
∆ (capital delta) – finite change
ε (epsilon) – electrical permittivity
θ (theta) – angle (rad or °)
κ (kappa) – dielectric constant (dimensionless)
λ (lambda) – wavelength (m), ), linear charge density (C/m)
µ (mu) – coefficient of friction (dimensionless), micro (prefix = 10-6), magnetic permeability
ν (nu) – frequency (Hz, s-1)
π (pi) – ratio of circumference to diameter (3.1416..)
ρ (rho) – density (kg /m3), resistivity (Ω•m)
σ (sigma) – surface charge density (C/m2), Stefan Boltzmann constant (5.6704 × 10-8 kg s-3 K-4)
∑ (capital sigma) – summation or sum of
τ (tau) – torque (N•m), time constant (s)
φ (phi) – angle (rad)
Φ (capital phi) – flux – either magnetic or electric
Ψ (psi) – wave function (dimensionless)
ω (omega) – angular velocity (rad/s)
Ω (capital omega) – Ohms (unit of resistance = V/A)
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K.K. AGRAWAL
1. ELECTROSTATICS
GIST




Electrostatics is the study of charges at rest.
Charging a body can be done by friction, induction and conduction.
Properties of charges:
o Like charges repel and unlike charges attract.
o Charges are additive in nature i.e., Q=∑𝑛𝑖=1 𝑞𝑖
o Charges are quantized. i.e., Q= ± ne [n=1,2,3,… & e=1.602 X10-19 C]
o Charge in a body is independent of its velocity & conserved
o Charge is measured in coulomb & stat coulomb
o 1 coulomb = 3 X 109 stat coulomb & 1 absolute coulomb = 3 X 1011 stat coulomb
Dielectric Constant, also called relative electrical permittivity of the medium and denoted by εr,
is thus given by
εr = ε/ ε0

To measure charge electroscopes are used

Coulomb’s law: 𝐹⃗ =
𝑘𝑞1 𝑞2
𝑟2
𝑟̂
1
k=4𝜋𝜀 = 9X109 Nm2c-2
0
Where, 𝜀0 = permittivity of free space
1/r2
Q1Q2<0
Q1Q2>0
F


Principle of superposition: F total = F12 + F 13 + ….
⃗⃗⃗𝑖 [vector sum of individual forces]
𝐹𝑡𝑜𝑡𝑎𝑙 = ∑𝑛𝑖=1 𝐹

q q 
1 2r 
2 12
4 r12
1
q q 
1 3 r  ....
2 13
4 r13
1
1/r2
F
E
Q
E

Note: In the above triangle the quantity shown at the vertex, could be arrived by multiplying
the quantities shown at the base, ie F=E X Q. Any one of the quantity shown at the base is
given by the ratio of the quantities shown at vertex & the other quantity shown at the base, i
e E=F/Q or Q= F/E
Electric field: Force experienced by a unit positive (or test) charge. It is a vector. SI unitNC-1.
4
K.K. AGRAWAL
E
r2

𝑘𝑄
𝐸⃗⃗ = 𝑟 2 𝑟̂

E  Lt

⃗⃗ =
Field due to a point charge: 𝐸

Principle of superposition: E total 


Dipole: Two equal and opposite charges separated by a small distance.
Dipole moment: Product of magnitude of charge and distance of separation between them. It is
a vector. SI unit: Cm, 𝑝⃗=Q.2𝑎⃗ ; direction of 𝑝⃗ is negative to positive charge.

Dipole in a uniform electric field experiences no net force and instead experiences a torque.
qo  0
F
qo
𝑘𝑄
𝑟2
𝑟̂

n
i 1
E r [vector sum of individual fields]
𝜏⃗=𝑝
⃗⃗⃗⃗ × 𝐸⃗⃗ ⇒ 𝜏⃗=|𝑝⃗||𝐸⃗⃗ | sin 𝜃 𝑛̂


If 𝜃= 0° ⇒ stable equilibrium; If 𝜃= 180° ⇒ unstable equilibrium.
Electric field due to a dipole
o
at a point in End on position or on the axial line:
⃗⃗
2kp
r3
along the direction of dipole
moment
o
at a point in Broad side on or on the equatorial line:
⃗⃗
kp
r3
opposite to the direction of
dipole moment.
o


at any point :
⃗⃗
kp
r3
√3 cos2 𝜃 + 1
When dipole is placed parallel to non-uniform field a resultant force will act on dipole due to
which it will move in the direction of force (translational motion)
When dipole is placed perpendicular to non-uniform field a couple will act on dipole as well as a
resultant force, due to which dipole will have rotational as well as translational

Electric field at any point on the axis of a uniformly charged ring : E

⃗⃗⃗⃗⃗⃗⃗. 𝐸⃗⃗ =|𝐸⃗⃗ ||∆𝑆
⃗⃗⃗⃗⃗| 𝑐𝑜𝑠 𝜃 ;
Electric flux: ∅=∆𝑆

It is a scalar; SI unit: NC-1m2 or V m.

Gauss’ theorem in electrostatics:∅𝑡𝑜𝑡𝑎𝑙
=
𝑞𝑡𝑜𝑡𝑎𝑙
5
𝜀0
= (r2
kqr
+a2 )3/2
K.K. AGRAWAL

Uniform Charge distribution:
Linear charge distribution: 𝜆 =
∆𝑞
[𝜆 ⇒ linear charge density Unit Cm-1]
∆𝑙
∆𝑞
Surface charge distribution: 𝜎 =
Volume charge distribution: 𝜌 =
∆𝑆
∆𝑞
[𝜎 ⇒ surface charge density Unit Cm-2]
∆𝑉
[𝜌 ⇒ Volume charge density Unit Cm-3]

Applications of Gauss’ theorem for uniform charge distribution:
Expression for Infinite
Infinite
plane Thin spherical shell
Linear
sheet
𝜎𝑠
𝜆𝑙
Flux ∅
𝜎4𝜋𝑟 2
𝜀0
𝜀0
𝜀0
𝑄
𝜆
Magnitude of
[for points on/outside the shell]
4𝜋𝑟 2 𝜀0
𝜎
2𝜋𝑟𝜀0
Field E
=0 [for points inside the shell]
𝜀0
𝜎
∆𝑞
∆𝑞
Charge density
𝜆=
𝜎=
4𝜋𝑟 2
∆𝑙
∆𝑆

Properties of electric field lines:
 Arbitrarily starts from +ve charge and end at –v e charge
 Continuous, but never form closed loops
 Never intersect
 Relative closeness of the field lines represents the magnitude of the field strength.
 For a set of two like charges – lateral pressure in between
 For a set of two unlike charges – longitudinal contraction in between.
Electrostatic Potential: Work done per unit positive Test charge to move it from infinity to that
point in an electric field. It is a scalar. SI unit: J/C or Volt

V=W/qo


1 volt = 1/300 esu volt, 1 stat volt =300 volts,
1 volt = 108 emu volt, 1 esu volt = 9 X 1010 emu volt

Electric potential for a point charge: 𝑉 =
6
𝑘𝑞
𝑟
K.K. AGRAWAL

Electric field is conservative. This means that the work done is independent of the path
followed and the total work done in a closed path is zero.

Potential due to a system of charges: v
total

𝑘 |𝑝⃗|

on its axial line: 𝑉𝑎𝑥𝑖𝑎𝑙 =

on its equatorial line: 𝑉𝑒𝑞 = 0

at any point:
𝑉𝑎𝑛𝑦 =
Potential difference

Potential energy of two charges:

ri
Potential due to a dipole at a point



  in1 kqi
𝑟2
⃗⃗⃗|
𝑘|𝑝
𝑐𝑜𝑠𝜃
𝑟2
𝑉𝐴 − 𝑉𝐵 = 𝑘𝑞 [
1
𝑟𝐴
U=
−
1
]
𝑟𝐵
𝑘𝑞1 𝑞2
𝑟
Potential energy of a dipole :
U=𝑝
⃗⃗⃗⃗. 𝐸⃗⃗ = p E [𝑐𝑜𝑠𝜃0 - 𝑐𝑜𝑠𝜃1 ]
Electrostatics of conductors
(i) Inside a conductor Electrostatic field is zero
(ii) On the surface E is always Normal
(iii) No charge inside the conductor but gets distributed on the surface
(iv) Charge distribution on the surface is uniform if the surface is smooth
(v) Charge distribution is inversely proportional to ‘r’ if the surface is uneven
(vi) Potential is constant inside and on the surface
Equipotential surfaces: The surfaces on which the potential is same everywhere.
 Work done in moving a charge over an equipotential surface is zero.
 No two equipotential surfaces intersect.
 Electric field lines are always perpendicular to the equipotential surfaces.
 As E= -
𝑑𝑉
𝑑𝑟
If V is constant, E ∝
1
𝑟
and if E is constant, V∝ 𝑟
7
K.K. AGRAWAL

Capacitor: A device to store charges and electrostatic potential energy.

Capacitance: C 



Q
, Ratio of charge and potential difference. Scalar,
V
SI unit: farad [F] & C.G.S. unit stat farad, 1 farad = 9 X109 stat farad
Capacity of a spherical conductor C = 4π𝜀 0 r
Combination of capacitors:
1
c
 Capacitors in series: 
n
1
c
i 1
 Capacitors in parallel: c 
i
n
c
i 1
i
Capacitance of a parallel plate capacitor: 𝐶
=
𝜀0 × 𝐴
𝑑
Capacitance of a parallel plate capacitor with a dielectric medium in between:
𝜖𝑜 𝐴

Cm =

If t=0 =>C0 =

If t=d =>C0 =k
𝑡
(𝑑−𝑡+𝑘)
𝜖𝑜 𝐴
(𝑑)
𝜖𝑜 𝐴
(𝑑)
=>Cm = k C0
Cm
Co
k

Combination of capacitors:

Energy stored in capacitors: U  CV 2  QV 
1
2
1
2
1 Q2
2 C
V

1
Q
Area shaded in the graph = U = 2 𝑄𝑉
8
K.K. AGRAWAL
1
𝜎2
2
2𝜀0

Energy density :𝑈𝑑

Introducing dielectric slab between the plates of the charged capacitor with:
Property⇣
Charge
Potential
difference
Electric
field
Capacitance
Energy
= 𝜀0 𝐸 2 =
Battery connected
K Q0
V0
Battery disconnected
Q0
V0/K
E0
E0/K
KC0
KC0
K
1
times2 𝜀0 𝐸 2 [Energy
1
1/K times2 𝜀0 𝐸 2 [Energy used for
is supplied
By battery]



Polarization]
On connecting two charged capacitors:
𝐶1 𝑉1 +𝐶2 𝑉2
Common Potential:
𝑉=
Loss of energy:
∆𝑈 = 2 𝐶1 +𝐶 2 (𝑉1 − 𝑉2 )2
𝑉1 +𝑉2
1 𝐶 ×𝐶
1
2
Non polar dielectrics:- The centre of positive charge coincide with the centre of negative
charge.
Polar dielectrics:- The centre of positive and negative charges do not coincide because of the
asymmetric shape of the molecules.

Induced dipole moment p = αϵ0E0


Dielectric constant K = E0/E
Electric susceptibility (ᵡ):- It describes the electric behavior of a dielectric.





K = 1+ᵡ
The maximum electric field that a dielectric medium can withstand without breaking down of
its insulating property is called its dielectric strength.
A lighting conductor is used to save big building from the damage by the lighting flashes.
The capacity of earth is only 711µF so in practice we use nanofarad (nF) and picofarad(pF)
Human heart beats, potential difference in the range of 1 milli volt.
Van de Graff generator: Is an electrostatic machine to build very high voltages.
1
1
 Works on the Principle 𝑉(𝑟) − 𝑉(𝑅) = 𝑘𝑞 (𝑟 − 𝑅) ;
 Corona discharge is the electrical discharge through the defected part of the spherical
conductor, where the surface is not smooth. Hence, the hollow spherical conductor in
the Van de Graff generator should have a smooth outer surface.
9
K.K. AGRAWAL
CONCEPT MAP
Electric Force /Field/ Potential / P.E.
𝐹=𝑘
𝑞1 𝑞2
𝑟2
𝑈=𝑘
(Unit : N)
𝐸=𝑘
𝑞1 𝑞2
𝑟
𝑉=𝑘
10
𝑞1
𝑟
𝑞1
𝑟2
(Unit N/C orV/m)
K.K. AGRAWAL
CONCEPT MAP
Charge and its impact
11
K.K. AGRAWAL
QUESTIONS
1-
Explain the frictional Electricity?
2-
Explain the electronic theory of origin of charge?
3-
What do you mean by conservation of charge? And Define quantization of charge?
4-
Explain the Coulomb’s law in electrostatic in different forms? Write its significance & limitations.
5-
Compare b/w the electrostatic & gravitational forces?
6-
Write the effect of presence of dielectric medium on the electrostatic force?
7-
Explain force b/w multiple charges or principle of superposition?
8-
Explain the distribution of charge through the charge density?
9-
Define the electric field and its intensity?
10-
Derive expression for electric field intensity due to a point charge?
11-
What are electric field lines or lines of force? Write their property.
12-
What is electric dipole? Give its examples.
13-
Derive an expression for electric field due to an electric dipole in end on or longitudinal or axial
position.
14-
Derive an expression for electric field due to an electric dipole in broad side on or transverse or
axial position.
15-
Derive an expression for torque on a dipole in a uniform electric field.
16-
Derive an expression for work done in turning a dipole?
17-
Derive an expression for potential energy of a dipole in uniform electric field?
18-
Define the electric flux? Write the factors affecting it?
19-
What is Gauss’ theorem? Prove it.
20-
Find the electric field intensity due to a point charge by using Gauss theorem?
21-
Find the Coulomb’s inverse square law by using Gauss theorem?
22-
By using Gauss theorem derive electric field intensity due to a uniformly conducting sphere
(spherical shell).
23-
By using Gauss theorem derive electric field intensity due to a uniformly non-conducting solid
sphere.
24-
By using Gauss theorem derive electric field intensity due to a uniformly charged cylindrical
conductor of infinite length.
25-
Find electric field intensity due to a uniformly charged linear conductor of infinite length?
12
K.K. AGRAWAL
26-
Find electric field intensity due an infinite uniformly to charged non-conducting sheet?
27-
Find electric field intensity due to an infinite uniformly charged conducting plane?
28-
Find electric field intensity due to two uniformly charged parallel infinite non-conducting plane
sheets.
29-
Define electric potential & potential difference? Write the factors affecting the potential.
30-
Derive expression for electric potential & potential difference due to a point charge?
31-
Find electric potential due to a dipole in longitudinal or end on position?
32-
Find electric potential due to a dipole in transverse or broad side on position?
33-
Derive relationship b/w the electric field intensity and electric potential?
34-
What is equipotential surface? Write their properties.
35-
Explain the motion of charged particle in an electric field and define electron volt?
36-
Explain the electrostatic potential energy & derive its formula?
37-
Define capacity of a conductor? Write its different units & dimensional formula.
38-
Find an expression for the capacity of an isolated spherical conductor? Write the factors affecting
it.
39-
Explain the principle of condenser & its capacity?
40-
Derive an expression for the capacity of a parallel plate condenser and write the factors affecting
it?
41-
Derive an expression for the capacity of a parallel plate condenser when there is partial dielectric
medium and the remaining medium is air?
42-
Derive an expression for the capacity of a spherical condenser and write the factors affecting it?
43-
Derive an expression for the capacity of a cylindrical condenser and the factors affecting it?
44-
Explain the combination of capacitors in parallel and series and derive expression for it?
45-
Explain the energy stored in charged capacitor?
46-
Explain the redistribution of charges b/w two charged conductor connected together?
47-
Prove that there is always loss of energy in redistribution of charges?
48-
Explain dielectrics and dielectric medium? Write its type.
49-
Explain the Van – de Graff generator on the following points:(i) Principle (ii) construction & diagram (iii) Working and use
------------------------------------------------------------------------------------------------------13
K.K. AGRAWAL
2. CURRENT ELECTRICITY
GIST
•
Current carriers – The charge particles which flow in a definite direction constitutes the electric
current are called current carriers. E.g.: Electrons in conductors, Ions in electrolytes, Electrons
and holes in semi-conductors.
•
Electric current is defined as the amount of charge flowing through any cross section of the
conductor in unit time. I = Q/t.
•
Current density J = I/A.
•
Ohm’s law: Current through a conductor is proportional to the potential difference across the
ends of the conductor provided the physical conditions such as temperature, pressure etc.
Remain constant. V α I i.e. V = IR, Where R is the resistance of the conductor. Resistance R is the
ratio of V & I
•
Resistance is the opposition offered by the conductor to the flow of current.
•
Resistance R = ρl/A where ρ is the resistivity of the material of the conductor- length and A area
of cross section of the conductor. If l is increased n times, new resistance becomes n2R. If A is
increased n times, new resistance becomes
1
R
n2
•
Resistivity ρ = m/ne2τ, Where m, n, e are mass, number density and charge of electron
respectively, τ-relaxation time of electrons. ρ is independent of geometric dimensions.
•
Relaxation time is the average time interval between two successive collisions
•
Conductance of the material G =1/R and conductivity σ=1/ρ
•
Drift velocity is the average velocity of all electrons in the conductor under the influence of
applied electric field. Drift velocity Vd = (eE/m)τ also I = neAvd
•
Mobility (μ) of a current carrier is the ratio of its drift velocity to the applied field  
•
Effect of temperature on resistance: Resistance of a conductor increase with the increase of
temperature of conductor RT  Ro (1  T ) , where α is the temperature coefficient of
resistance of the conductor. α is slightly positive for metal and conductor, negative for
semiconductors and insulators and highly positive for alloys.
•
Combination of resistors:
•
Cells: E.M.F of a cell is defined as the potential difference between its terminals in an open
circuit. Terminal potential difference of a cell is defined as the p.d between its ends in a closed
circuit.
Internal resistance r of a cell is defined as the opposition offered by the cell to the flow of
•
Rseries  R1  R2  ...Rn ,
1
RParallel

E 
1 R where R is external resistances.
V

current. r = 
•
Grouping of cells :
i) In series grouping circuit current is given by I s 
14
nE
,
R  nr
Vd
E
1
1
1

 ...
R1 R2
Rn
K.K. AGRAWAL
ii) In parallel grouping circuit current is given by I p 
•
mE
where n, m are number of cells in
r  mR
series and parallel connection respectively.
Kirchhoff’s Rule:
i) Junction Rule:-The algebraic sum of currents meeting at a point is zero.
I  0
ii) Loop rule:-The algebraic sum of potential difference around a closed loop is zero
•
Wheatstone bridge is an arrangement of four resistors arranged in four arms of the bridge and is
used to determine the unknown resistance in terms of other three resistances. For balanced
Wheatstone Bridge,
•
P R

Q S
Slide Wire Bridge or Metre Bridge is based on Wheatstone bridge and is used to measure
unknown resistance. If unknown resistance S is in the right gap, s   100  l  R

•
•
•
•
V  o
l

Potentiometer is considered as an ideal voltmeter of infinite resistance.
Principle of potentiometer: The potential drop across any portion of the uniform wire is
proportional to the length of that portion of the wire provided steady current is maintained in it
i.e. v α l
Potentiometer is used to (i) compare the e.m.f.s of two cells (ii) determine the internal resistance
of a cell and (iii) measure small potential differences.
Expression for comparison of e.m.f of two cells by using potentiometer,
 1 l1
 where l1 , l2 are
 2 l2
the balancing lengths of potentiometer wire for e.m.fs 1 and  2 of two cells.
•
Expression for the determination of internal resistance of a cell I is given by  l1  l2  R
 l 
 2 
Where l1 is the balancing length of potentiometer wire corresponding to e.m.f of the cell, l2 that
of terminal potential difference of the cell when a resistance R is connected in series with the cell
whose internal resistance is to be determined
•
•
•
•
•
   rl
 . Where L is the length of
Rr L
Expression for determination of potential difference V   
the potentiometer wire, l is balancing length, r is the resistance of potentiometer wire, R is the
resistance included in the primary circuit.
Joule’s law of heating states that the amount of heat produced in a conductor is proportional to
(i) square of the current flowing through the conductor,(ii) resistance of the conductor and (iii)
time for which the current is passed. Heat produced is given by the relation H=I2Rt
Electric power: It is defined `as the rate at which work is done in maintaining the current in
electric circuit. P =VI = I2R =V2/R. Power P is the product of V & I
Electrical energy: The electrical energy consumed in a circuit is defined as the total work done in
maintaining the current in an electrical circuit for a given time.
Electrical energy = VIt = I2Rt =(V2/R)t = Pt
Commercial unit of energy 1KWh= 3.6×106J
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K.K. AGRAWAL
•
Colour coding : Black Brown Red Orange Yellow Green Blue Violet Gray White
0
1
2
3
4
5
6
7
8
9
Tolerance (i) Gold 5%
(ii) Silver 10% (iii) No Color 20%
Example: if colour code on carbon resister is Red Yellow and Orange with tolerance colour as
silver, the resistance of the given resister is (24×103 ± 10%)Ω
 Colour code (carbon resistance) can be remembered by the following way
B. B. ROY of Great Britain has Very Good Wife.
CONCEPT MAP
Flow of Charges
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K.K. AGRAWAL
QUESTIONS
1-
Define electric current and current density?
2-
Explain the drift velocity and derive relation b/w current and drift velocity?
3-
What is ohm’s law? Derive ohm’s law on the basis of free electron model?
4-
Explain electrical resistance and write the factors affecting it?
5-
Define the following:(i) Electrical conductance (ii) Specific resistance or resistivity
(iii) Specific conductivity
6-
Write Ohm’s law in terms of specific conductivity or specific resistance?
7-
Explain the effect of temperature on resistance and specific resistance?
8-
Derive an expression for effective resistance in series and parallel combination?
9-
Explain Kirchhoff’s laws of current distribution?
10-
Explain Wheatstone’s bridge on the following points:(i) Principle (ii) construction & diagram (iii) derivation of formula?
11-
Explain Metre Bridge and its use in measurement of resistance of wire on the following points:(i) Description of the apparatus (ii) Derivation of formula (iii) Observation table (iv) Precautions.
12-
Define Ohmic and non ohmic resistances.
13-
Explain Thermistor and write its use?
14-
What do you mean by superconductivity? Write is cause and uses
15-
Explain colour code of carbon resistances
16-
What is electrolysis? Explain it
17-
Write Faraday’s laws of electrolysis?
18-
Explain water voltameter by construction and working?
19-
Explain copper voltameter by construction and working?
20-
Explain silver voltameter by construction and working?
21-
What is electric cell and write the difference b/w primary and secondary cell?
22-
Explain the simple voltaic cell by construction and chemical reaction?
17
K.K. AGRAWAL
23-
Explain the defect of simple voltaic cell and write its remedies?
24-
Explain the Leclanche cell by construction and chemical reaction?
25-
Explain the Daniel cell by construction and chemical reaction?
26-
Explain Lead accumulator by charging and discharging?
27-
Explain Ni – Fe cell or Alkali accumulator by construction and working?
28-
Define capacity and efficiency of an accumulator?
29-
Compare the Lead accumulator and Ni – Fe cell?
30-
Define E.M.F. and potential difference?
31-
Write difference b/w E.M.F. and terminal voltage or potential difference?
32-
What do mean by internal resistance of a cell and write the factor affecting it?
33-
Derive relation b/w E.M.F. , potential difference and internal resistance?
34-
Explain the series combination of n cell and find the current flowing in the combination?
35
Explain the parallel combination of m cell and find the current flowing in the combination?
36-
Explain the mixed combination of mn cell and find the condition for maximum current?
37-
Explain the potentiometer on the following point:(i) Construction (ii) formula (iii) potential gradient (iv) uses .
38-
Write difference b/w potentiometer and a voltmeter?
39-
Explain the sensitivity of potentiometer?
40-
Explain the use of potentiometer to compare the e .m. f. of two cell on the following points:(i) circuit diagram (ii) Principal and derivation of formula (iii) observation table (iv) precautions.
41-
Explain the use of potentiometer to find the internal resistance of a cell on the following points:(i) circuit diagram (ii) Principal and derivation of formula (iii) observation table (iv) precautions.
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