Free Printable Class 12 Half Yearly Exam Revision

1.

Which method of charging does not require materials to be in physical contact with each other?

a)

Conduction

b)

Induction

c)

Friction

d)

None of these

2.

An electric dipole having dipole moment q2l is placed inside a hollow conductor. The electric flux through the conductor is:

a)

q / ε_o

b)

q

c)

2ε_o

d)

zero

3.

A spherical conductor has a charge +q placed inside it. If the radius of the sphere is doubled, flux through the conductor will:

a)

become twice

b)

become half

c)

become zero

d)

will not change

4.

Work done in moving a charge +q across an equipotential surface having potential V_o is:

a)

W = q V_o

b)

W = $\int_{ }^{ }F\ .dl$

c)

W = -q V_o

d)

Zero

5.

Electric Field due to an electric dipole at axial point is given by:

a)

E = $\frac{1}{4\pi\epsilon\circ}\left(\frac{2p}{r^3}\right)$

b)

E = $\frac{1}{4\pi\epsilon\circ}\left(\frac{p}{r^3}\right)$

c)

E = $\frac{1}{4\pi\epsilon\circ}\left(\frac{2p}{r^2}\right)$

d)

E = $\frac{1}{4\pi\epsilon\circ}\left(\frac{p}{r^2}\right)$

6.

Torque on an electric dipole placed in an electric field is given by:

a)

$\tau\ =\ p\ E\ \sin\theta$

b)

$\tau\ =\ p\ E\ \cos\theta$

c)

$\tau\ =\ q\ \times2l$

d)

$\tau\ =0$

7.

Electrostatic potential energy of the given charges placed 'r' distance away is:

a)

$U\ =\ \frac{\ \ q_1\ q_2}{4\pi\epsilon\circ\ r^2}$

b)

$U\ =\ \frac{\ \ q_1\ q_2}{4\pi\epsilon\circ\ r}$

c)

$U\ =\ \frac{\ \ q_1\ q_2}{4\pi\epsilon\circ\ r^3}$

d)

U = 0

8.

Which of the following is not a correct expression for energy stored in a capacitor?

a)

$C\ =\ \frac{1}{2}\ C\ V\ ^2$

b)

$C\ =\ \frac{Q^2}{2C}\$

c)

$C\ =\ \frac{1}{2}QV$

d)

$C\ =\ \frac{1}{2}Q\ V^2$

9.

a)

$C_{eq}\ =\ C_{1\ }+\ \ C_{2\ }+C_{3\ }+\ \ C_{4\ }+\ \ldots$

b)

$\frac{1}{C_{eq}\ }=\ \frac{1}{C_1}+\frac{1}{C_2}+\cdots$

c)

None of these

10.

If a dielectric having dielectric constant 'k' is inserted between the plates of a parallel plate capacitor, the Capacitance:

a)

becomes C/k

b)

becomes k times C

c)

does not change

d)

becomes zero

11.

Relationship between emf, terminal voltage and internal resistance is: (While the cell is discharging)

a)

E = V - Ir

b)

V = E - Ir

c)

Ir = V - E

d)

r = (E + V) /I

12.

Resistance of a material depends on ?

a)

Length

b)

Area of Cross Section

c)

Material of the conductor (specific resistance)

d)

Temperature

13.

The Resistance of a wire is 2 Ω. If the Area of cross section of the wire is halved, and its length doubled, new Resistance is:

a)

2 Ω

b)

4 Ω

c)

8 Ω

d)

16 Ω

14.

Kirchhoff's Junction Law if based on the conservation of?

a)

Mass

b)

Energy

c)

Charge

d)

Momentum

15.

Kirchhoff's Loop Law if based on the conservation of?

a)

Mass

b)

Energy

c)

Charge

d)

Momentum

16.

In balanced condition (P/Q = R/S) of a wheatstone bridge, the current flowing through the Galvanometer is?

a)

Maximum

b)

Minimum

c)

Zero

d)

None of these

17.

Force on a charge 'q' moving with velocity 'v' in a uniform magnetic field 'B' is given by:

a)

F = q (v x B)

b)

F = q (B x v)

c)

F = v (q x B)

d)

F = q (v B cos θ )

18.

Magnetic force on a charge moving parallel to a uniform magnetic field B is"

a)

qvB

b)

qvB / 2

c)

zero

d)

2 (qvB)

19.

Correct expression for Lorentz Force is:

a)

F =q E

b)

F = q (v X B)

c)

F = qE + q (v X B)

d)

All of these

20.

S.I. unit of magnetic flux is:

a)

Tesla

b)

Gauss

c)

Weber

d)

Ampere

21.

1 Gauss = _ Tesla

a)

10 ^-4

b)

1/100

c)

1000

d)

200

22.

S.I. Unit of magnetic flux is:

a)

Tesla

b)

Gauss

c)

Weber

d)

Ampere

23.

Magnetic Field at the centre of the given loop having radius 'a' is?

a)

$\frac{\mu o\ i}{2\ a}\$

b)

$\mu o\ i\$

c)

zero

d)

none of these

24.

The magnetic field in the core of a solenoid having length 'l' and number of turns 'N' is:

a)

$\mu o\ N\ i$

b)

$\mu o\ \frac{N}{l}\ i$

c)

$\frac{\mu oNi}{4\pi}$

d)

$\mu o\ i$

25.

For a Ferromagnetic Material, the value of Susceptibility $\chi$ is:

a)

zero

b)

=1

c)

<0

d)

>>1

26.

The area enclosed by a hysteresis loop is the measure of:

a)

retentivity

b)

susceptibility

c)

permeability

d)

energy loss per cycle

27.

The SI Unit of Inductance is:

a)

Tesla

b)

Farad

c)

Henry

d)

Gauss

28.

Lenz's law is a consequence of law of conservation of?

a)

Energy only

b)

Charge only

c)

Momentum only

d)

Energy and momentum

29.

Determine the direction of induced current in the given loop:

a)

Clockwise

b)

Anticlockwise

c)

None of these

30.

The formula to calculate capacitive reactance Xc is:

a)

ω C

b)

1 / ω C

c)

1 / C

d)

C

Class 12 Half Yearly Exam Revision

Total questions: 30

Worksheet time: 16mins

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