Free Printable ELECTROSTATICS (XII)

1.

1. Force of attraction between two point charges Q and – Q separated by d is F . When these charges are placed on two identical spheres of radius R=0.3d whose centres are distance d apart, the force of attraction between them is

a)

Greater than F

b)

EQUAL TO F

c)

Less than F

d)

INITIALLY Less than F THEN FINALLY EQUAL TO F

2.

2. One metallic sphere A is given positive charge whereas another identical metallic sphere B of exactly same mass as of A is given equal amount of negative charge. Then

a)

(a) Mass of A and mass of B still remain equal

b)

(b) Mass of increases A

c)

(c) Mass of decreases B

d)

(d) Mass of increases B

3.

Four metal conductors having different shapes

1. A sphere 2. Cylindrical

3. Pear 3. Lightning conductor

are mounted on insulating stands and charged. The one which is best suited to retain the charges for a longer time is

a)

1

b)

2

c)

3

d)

4

4.

A charge q is placed at the centre of the line joining two equal charges Q. The system of the three charges will be in equilibrium, if q is equal to

a)

$-\frac{Q}{2}$

b)

$-\frac{Q}{4}$

c)

$+\frac{Q}{4}$

d)

$+\frac{Q}{2}$

5.

The electric potential V at any point O (x, y, z all in metres) in space is given by V= 4 $X^2$ . The electric field at the point (1,0,2) in volt/m is

a)

8 along negative X axis

b)

8 along positive X axis

c)

16 along negative X axis

d)

16 along positive X axis

6.

A hollow metal sphere of radius 5 cm is charged so that the potential on its surface is 10 V. The potential at the centre of the sphere is

a)

0V

b)

10V

c)

Same as at point 10 cm away from the surface

d)

Same as at point 25 cm away from the surface

7.

If a unit positive charge is taken from one point to another over an equipotential surface, then

a)

Work is done on the charge

b)

Work is done by the charge

c)

Work done is constant

d)

No work is done

8.

Electric lines of force about negative point charge are

a)

Circular, anticlockwise

b)

Circular, clockwise

c)

Radial, inward

d)

Radial, outward

9.

Two charged spheres of radii 10 cm and 15 cm are connected by a thin wire. No charge will flow, if they have

a)

The same charge on each

b)

The same potential

c)

The same energy

d)

The same field on their surfaces

10.

$Ch\arg es\ of\ \frac{10}{3}\times10^{-9}C$

are placed at each of the four corners of a square of side 8cm . The potential at the intersection of the diagonals is

a)

$150\sqrt{2\ }volt$

b)

$1500\sqrt{2\ }\ volt$

c)

$900\sqrt{2}\ volt$

d)

900 volt

11.

Three charges are located at the vertices of an equilateral triangle. At the centre of the triangle

a)

The field is zero but potential is non-zero

b)

The field is non-zero but potential is zero

c)

Both field and potential are zero

d)

Both field and potential are non-zero

12.

An electron and a proton are in a uniform electric field, the ratio of their accelerations will be

a)

Zero

b)

Unity

c)

The ratio of the masses of proton and electron

d)

The ratio of the masses of electron and proton

13.

Two parallel plates have equal and opposite charge. When the space between them is evacuated, the electric field between the plates is $2\ \times10^{5\ }$ v/m . When the space is filled with dielectric, the electric field becomes $1\times10^5$ v/m. The dielectric constant of the dielectric material

a)

1/2

b)

1

c)

2

d)

$2\times10^5$

14.

The distance between the two charges $25\mu C$ and $36\mu C$ is 11cm. At what point on the line joining the two, the intensity will be zero

a)

At a distance of 5cm from $25\mu C$

b)

At a distance of 5cm from $36\mu C$

c)

At a distance of 10cm from $25\mu C$

d)

At a distance of 10cm from $36\mu C$

15.

The unit of electric field is not equivalent to

a)

N/C

b)

V/m

c)

J/C

d)

$JC^{-1}m^{-1}$

16.

Two charge and are situated at a certain distance. At the point exactly midway between them

a)

Electric field and potential both are zero

b)

Electric field is zero but potential is not zero

c)

Electric field is not zero but potential is zero

d)

Neither electric field nor potential is zero

17.

A charge of 5C is given a displacement of 0.5m . The work done in the process is 10J . The potential difference between the two points will be

a)

2V

b)

0.25V

c)

1V

d)

25V

18.

Two charges of $\ 4\mu C$ each are placed at the corners A and B of an equilateral triangle of side length 0.2 m in air. The electric potential at C is

a)

$9\times10^4\ V$

b)

18\times10^4V

c)

$36\times10^4V$

d)

$36\times10^{-4}V$

19.

Two positive point charges of

$12\mu C$
and $8\mu C$ are 10cm apart. The work done in bringing them 4 cm closer is

a)

5.8J

b)

5.8eV

c)

13J

d)

13eV

20.

The potential at a point, due to a positive charge of

100 μ C

at a distance of 9m, is

a)

$10^4V$

b)

10^5V

c)

$10^{6\ }V$

d)

$10^7V$

21.

Two electric charges $12\mu C$ and $-6\mu C$ are placed 20 cm apart in air. There will be a point P on the line joining these charges and outside the region between them, at which the electric potential is zero. The distance of P from charge $-6\mu C$ is

a)

0.10m

b)

0.15m

c)

0.20m

d)

0.25m

22.

An electron is moving towards x-axis. An electric field is along y-direction then path of electron is

a)

Circular

b)

Elliptical

c)

Parabola

d)

None of these

23.

Two spheres A and B of radius ‘a’ and ‘b’ respectively are at same electric potential. The ratio of the surface charge densities of A and B is

a)

$\frac{a}{b}$

b)

$\frac{b}{a}$

c)

$\frac{a^2}{b^2}$

d)

$\frac{b^2}{a^2}$

24.

Electric field intensity at a point in between two parallel sheets with like charges of same surface charge densities $\sigma$ is

a)

$\frac{\sigma}{2\epsilon_0}$

b)

$\frac{\sigma}{\epsilon_0}$

c)

zero

d)

$\frac{2\sigma}{\epsilon_0}$

25.

A hollow sphere of radius 1m and charge Q does not produce an electric field at any

a)

Point beyond 2 metres

b)

Point beyond 10 metres

c)

Interior point

d)

Outer point

26.

Two point charges 9e and e are at 16 cm away from each other. Where should another charge q be placed between them so that the system remains in equilibrium

a)

24 cm from 9e

b)

12 cm from 9e

c)

24 cm from e

d)

12 cm from e

27.

An electron enters in high potential region V2 from lower potential region V1 then its velocity

a)

Will increase

b)

Will change in direction but not in magnitude

c)

No change in direction of field

d)

No change in direction perpendicular to field

28.

Equipotential surfaces associated with an electric field which is increasing in magnitude along the x-direction are

a)

Planes parallel to yz-plane

b)

Planes parallel to xy-plane

c)

Planes parallel to xz-plane

d)

Coaxial cylinders of increasing radii around the x-axis

29.

An electric dipole is placed in an electric field generated by a point charge

a)

The net electric force AND torque on the dipole must be zero

b)

The net electric force and torque on the dipole may not be zero

c)

The torque on the dipole due to the field must be zero

d)

The force on the dipole due to the field must be zero

30.

An electric dipole placed parallel to a uniform electric field experiences

a)

Force and torque both

b)

Force but no torque

c)

Torque but no force

d)

No force and no torque

31.

Intensity of an electric field E due to a dipole, depends on distance r as

a)

$E\alpha\ \frac{1}{r}$

b)

$E\alpha\ \frac{1}{r^2}$

c)

$E\ \alpha\ \frac{1}{r^3}$

d)

$E\ \alpha\ \frac{1}{r^4}$

32.

What is the angle between the electric dipole moment and the electric field strength due to it on the equatorial line

a)

0^o

b)

90^o

c)

180^o

d)

None of these

33.

Electric field at a point varies as for $r^0$

a)

An electric dipole

b)

A point charge

c)

A plane infinite sheet of charge

d)

A line charge of infinite length

34.

Choose the incorrect statement from the following: When two identical capacitors are charged individually to different potentials and connected PARALLEL to each other after disconnecting them from the source

a)

Net charge equals the sum of initial charges

b)

The net energy stored in the two capacitors is less than the sum of the initial individual energies

c)

The net potential difference across them is different from the sum of the individual initial potential difference

d)

The net potential difference across them equals the sum of the individual initial potential differences

35.

A 20F capacitor is charged to 5V and isolated. It is then connected in parallel with an uncharged 30F capacitor. The decrease in the energy of the system will be

a)

25J

b)

200J

c)

125J

d)

150J

36.

While a capacitor remains connected to a battery and dielectric slab is applied between the plates, then

a)

Potential difference between the plates is changed

b)

Charge flows from the battery to the capacitor

c)

Electric field between the plates increases

d)

Energy store in the capacitor decreases

37.

A metallic sheet is inserted between the plates of a parallel plate capacitor. The capacitance of the capacitor

a)

Increases

b)

Is dependent of the position of the sheet

c)

Is maximum when the metal sheet in the middle

d)

Is maximum when the metal sheet touches one of the capacitor plates

38.

The capacity of the conductor does not depend upon

a)

Charge

b)

Voltage

c)

Nature of the material

d)

All of these

39.

A parallel plate air capacitor is charged to a potential difference of V. After disconnecting the battery, distance between the plates of the capacitor is increased using an insulating handle. As a result, the potential difference between the plates

a)

Decreases

b)

Increases

c)

Becomes zero

d)

Does not change

40.

Sixty-four drops are jointed together to form a bigger drop. If each small drop has a capacitance C, a potential V, and a charge q, then the capacitance of the bigger drop will be

a)

C

b)

4C

c)

16C

d)

64C

ELECTROSTATICS (XII)

Total questions: 40

Worksheet time: 23mins

Similar Resources on Wayground