Electrostatics Magnetic Effect of Current, NCERT Physics Class 12, MCQ Quiz Test

MCQ 1:
The wire loop formed by joining two semicircular sections of radii R₁ and R2, and centre C, carries a current I, as shown. The magnetic field at C has magnitude –

MCQ 2:
B along the axis of a solenoid is given by –

MCQ 3:
Magnetic field is not associated with

A charge in uniform motion An accelerated charge A decelerated charge A stationary charge

MCQ 4:
A current-carrying, straight wire is kept along the axis of a circular loop carrying a current. The straight wire:

Will exert an inward force on the circular loop Will exert an outward force on the circular loop Will not exert any force on the circular loop Will exert a force on the circular loop parallel to itself

MCQ 5:
A vertical wire carries a current in upward direction. An electron beam sent horizontally towards the wire will be deflected

Towards right Towards left Upwards Downwards

MCQ 6:
If the electric field is uniform, then the electric lines of forces are -

Divergent Convergent Circular Parallel

MCQ 7:
Electric lines of forces-

Exist everywhere Are imaginary Exist only in the immediate vicinity of electric charges None of the above

MCQ 8:
Which one of the following diagrams shows the correct lines of force ?

MCQ 9:
In fig. shown the electric lines of force emerging from a charged body. If the electric fields at A and B are E_A and E_B are respectively and the distance between A and B is r then -

E_A > E_B E_A < E_B E_A = E_B E_A = E_B / r²

MCQ 10:
A metallic solid sphere is placed in a uniform electric field. The lines of force follow the path(s) shown in figure as

1 2 3 4

MCQ 11:
Three positive charges of equal value q are placed at the vertices of an equilateral triangle. The resulting lines of force should be sketched as in –

MCQ 12:
A point charge ‘q’ is placed at a point inside a hollow conducting sphere which of the following electric lines of force pattern is correct ?

MCQ 13:
A few electric field lines for a system of two charges Q1 and Q2 fixed at two different points on the x-axis are shown in the figure. These lines suggest that -

|Q₁| > |Q₂| |Q₁| < |Q₂| At a finite distance to the left of Q₁ the electric field is zero At a finite distance to the right of Q₂ the electric field is zero

MCQ 14:
F_g and F_e represent the gravitational and electrostatic force respectively between two protons situated at some distance in vacuum. The ratio of F_g to F_e is of the order of

10^–43 10¹ 10⁰ 10^–36

MCQ 15:
When the distance between two charged particle is halved, the force between them becomes -

One fourth One half Double Four times

MCQ 16:
A certain charge Q is divided at first into two parts, (q) and (Q–q). Later on the charges are placed at a certain distance. If the force of interaction between the two charges is maximum then-

(Q/q) = (4/1) (Q/q) = (2/1) (Q/q) = (3/1) (Q/q) = (5/1)

MCQ 17:
Three equal charges (q) are placed at corners of a equilateral triangle. The force on any charge is -

Zero

MCQ 18:
Two charges 9e and 3e are placed at a distance r. The distance of the point where the electric field intensity will be zero is -

MCQ 19:
Six charges +Q each are placed at the corners of a regular hexagon of side (a), the electric field at the centre of hexagon is-

Zero

MCQ 20:
A uniformly charged rod with charge per unit length λ is bent in to the shape of a semicircle of radius R. The electric field at the centre is -

2kλ/R kλ/2R Zero None

MCQ 21:
If an electric dipole is kept in a uniform electric field. Then it will experience-

a force a couple and moves a couple and rotates a force and moves

MCQ 22:
An electric dipole consists of two opposite charges each of magnitude 1 × 10^–6 C separated by a distance 2 cm. The dipole is placed in an external field of 10 × 10⁵ N/C. The maximum torque on the dipole is -

0.2 x 10^–3 N-m 1.0 x 10^–3 N-m 2 x 10^–2 N-m 4 x 10^–3 N-m

MCQ 23:
The ratio of the electric field due to an electric dipole on its axis and on the perpendicular bisector of the dipole is-

1 : 2 2 : 1 1 : 4 4 : 1

MCQ 24:
A hemisphere (radius R) is placed in electric field as shown in fig. Total outgoing flux is -

πR²E 2πR²E 4πR²E (πR²E)/2

MCQ 25:
Two large metal plates each of area (A) carry charges +q and -q and facing each other. The plates are separated by a small distance (d) the electric field between the plates would be -