Moving Charges and Magnetism — Physics STD 12 Science — Question

Electric charges of +10μC, + 5μC, -3μC and +8 μC  are placed at the corners of a square of side  m. the potential at the centre of the square is

(a) 1.8 V

(b)  V

(c) 1.8

(d) 1.8  V

If a proton and electron have same de Broglie wavelength, then:

One conducting sphere has 50e charge and the other identical sphere has + 20e charge. If both the sphere are touched and separated, then the charge on each will be:

Which curve may best represent the current deflection in a tangent galvanometer

(a) A

(b) B

(c) C

(d) D

A long, straight wire of radius R carries a current distributed uniformly over its cross section. T he magnitude of the magnetic field is:

1. Maximum at the axis of the wire.
2. Minimum at the axis of the wire.
3. Maximum at the surface of the wire.
4. Minimum at the surface of the wire.

Whenever the magnetic flux linked with a coil changes, an induced e.m.f. is produced in the circuit. The e.m.f. lasts

Two lines of force due to a bar magnet

(a) Intersect at the neutral point

(b) Intersect near the poles of the magnet

(c) Intersect on the equatorial axis of the magnet

(d) Do not intersect at all

A circular coil of radius 4 cm has 50 turns. In this coil a current of 2 A is flowing. It is placed in a magnetic field of 0.1 . The amount of  work done in rotating it through 180°  from its equilibrium position will be

(a) 0.1 J

(b) 0.2 J

(c) 0.4 J

(d) 0.8 J

Which of the following is used in the Davisson – Germer experiment?