MCQs of Electric Charges and Electric Fields

Electric Charges and Electric Fields MCQs

MCQs of Electric Charges and Electric Fields

Showing 111 to 120 out of 141 Questions

111.

A uniformly charged wire passes through a cube of side length a. If the linear charge density on the wire is λ, then the maximum electric flux passing through the cube is _____.

(a)	$\frac{6 λ a^{2}}{ε_{0}}$
(b)	$\frac{\sqrt{2} λ a}{ε_{0}}$
(c)	$\frac{\sqrt{3} λ a}{ε_{0}}$
(d)	$\frac{λ a}{ε_{0}}$

112.

Electric flux going in and coming out of the closed surface are respectively 8 × 10³ and 4 × 10³ units. So electric charge in a closed surface is _____.

(a)	4 × 10³ C
(b)	-4 × 10³ C
(c)	$- 4 \times 10^{3} ε_{0} C$
(d)	$\frac{- 4 \times 10^{3}}{ε_{0}} C$

113.

A square surface of side L metre is in the plane of paper. If an uniform electric field

\vec{E}

(volt/m) also in the plane of paper is limited only to the lower half of the square surface, then the electric flux in SI unit associated with the surface is _____.

(a)	EL²
(b)	$\frac{E L^{2}}{2 ε_{0}}$
(c)	$\frac{E L^{2}}{2}$
(d)	zero

114.

If the repulsive force, acting between two particles of mass 1.6 × 10^-27 kg and charge 1.6 × 10^-19 C separate by a certain distance, is equal to the weight of one of them, then the distance between them is _____ m. (k = 9 × 10⁹ MKS and g = 10 ms^-2)

(a)	0.012
(b)	0.12
(c)	1.44
(d)	1.44 × 10^-2

115.

Two identical conducting spheres carrying different opposite charges attarct each other with a force F when placed in air at a distance 'd' apart. The spheres are brought into contact and then taken to their original positions. Now, the two spheres repel each other with a force whose magnitude is equal to that of the initial attractive force. The ratio between initial charges on the spheres is_____.

(a)	$- (3 + \sqrt{8}) only$
(b)	$- 3 + \sqrt{8} only$
(c)	$- (3 + \sqrt{8}) or (- 3 + \sqrt{8})$
(d)	$+ \sqrt{3}$

116.

A charge Q is placed at each of the opposite corners of a square. Another charge q is placed at each of the other two corners. If the net electrical force on Q is zero, then

\frac{Q}{q}

= _____.

(a)	$- 2 \sqrt{2}$
(b)	-1
(c)	1
(d)	$- \frac{1}{\sqrt{2}}$

117.

A charge Q is divided into two parts q and Q - q. If the coulomb repulsion between them, when they are separated, is maximum, then the ratio of

\frac{Q}{q}

should be _____.

(a)	2
(b)	$\frac{1}{2}$
(c)	4
(d)	$\frac{1}{4}$

118.

PQR is a right angle triangle in which PQ = 3 m and QR = 4 m and

∠ P Q R = \frac{π}{2}

. The three charges +15 C, +12 C and -20 C are placed respectively on P, Q and R. The force acting on Q is _____.(Here, k is a coulomb's constant)

(a)	125 k N
(b)	25 k N
(c)	zero
(d)	35 k N

119.

Electrical force between two point charges is 200 N. If we increase 10% charge on one of the charges and decrease 10 % charge on the other, then the electrical force between them for the same distance is _____ N.

(a)	200
(b)	99
(c)	198
(d)	100

120.

Two spheres A and B of radius 4 cm and 6 cm are given charges of 80 µC and 40 µC respectively. If they are connected by a fine wire, then the amount of charge flowing from one to other will be _____.

(a)	16 µC from A to B
(b)	20 µC from A to B
(c)	32 µC from B to A
(d)	32 µC from A to B

Showing 111 to 120 out of 141 Questions