MCQs of Electric Charges and Electric Fields

Electric Charges and Electric Fields MCQs

MCQs of Electric Charges and Electric Fields

Showing 41 to 50 out of 141 Questions

41.

A cube of side 10 cm encloses a charge of 0.1 µC. The number of electric lines of force emitted through each face of the cube is _____ .

(a)	1542
(b)	1642
(c)	1782
(d)	1883

42.

An attractive force of 9 N is effective between two charges of +5 µC. These charges are mutually touched and again placed at the same distance apart. The effective force will be _____ .

(a)	∞
(b)	0
(c)	9 × 10⁹ N
(d)	1 N

43.

The electric flux from a cube of edge a is Φ. What will be its value if edge of cube is 3a and charge enclosed is doubled ?

(a)	Φ
(b)	2Φ
(c)	$\frac{ϕ}{2}$
(d)	$\frac{ϕ}{4}$

44.

A is a spherical conductor placed concentrically inside a hollow spherical conductor B. If Q charge is given to A and B is earthed, then the electric intensity is not zero _____ .

(a)	inside A
(b)	outside B
(c)	on the surface of B
(d)	between A and B

45.

Assuming that a positive charge Q is uniformly distributed over the surface of a shell, the field at a distance r from the centre of the shell where r = R (R being the radius of the shell), is _____ .

(a)	$\frac{Q}{ε_{0} 4 π (2 R)^{2}}$
(b)	$\frac{Q}{ε_{0} 4 π R^{2}}$
(c)	$\frac{Q}{ε_{0} 4 π (3 R)^{2}}$
(d)	None of the above

46.

The electric field, due to a cylindrical charge distribution of infinite length at a distance equal to its radius from its surface, will be _____.(λ = linear charge density, R = radius of the cylinder)

(a)	$\frac{2 k λ}{R}$
(b)	$\frac{k λ}{R}$
(c)	$\frac{k λ}{2 R}$
(d)	$\frac{3 k λ}{2 R}$

47.

A thick metallic spherical shell of inner radius r₁ and outer radius r₂ has a charge +Q. A charge +q is placed at the centre of the shell. The charge per unit area on the outer surface is _____ .

(a)	$\frac{(Q - q)}{4 π ({r_{2}}^{2} - {r_{1}}^{2})}$
(b)	$\frac{(Q - q)}{4 π {r_{2}}^{2}}$
(c)	$\frac{(Q + q)}{4 π {r_{2}}^{2}}$
(d)	$\frac{(Q + q)}{4 π ({r_{2}}^{2} + {r_{1}}^{2})}$

48.

The force acting between two point charges kept at a certain distance is Φ. Now magnitudes of charges are doubled and distance between them is halved, the force acting between them is____.

(a)	Φ
(b)	4Φ
(c)	8Φ
(d)	16Φ

49.

An electric dipole is placed in a uniform field. The resultant force acting on it _____.

(a)	always be zero
(b)	depends on its relative position
(c)	never be zero
(d)	depends on its dipole moment.

50.

An electric dipole is placed in an electric field of a point charge, then _____

(a)	the resultant force acting on the dipole always zero
(b)	the resultant force acting on the dipole may be zero
(c)	torque acting on it may be zero
(d)	torque acting on it is always zero.

Showing 41 to 50 out of 141 Questions