Moving Charges and Magnetism — Physics STD 12 Science — Question

The time period of a thin bar magnet in earth’s magnetic field is T. If the magnet is cut into two equal parts perpendicular to its length, the time period of each part in the same field will be

(a)

(b) T

(c)

(d) 2T

Compton effect shows that

(a) X-rays are waves	(b) X-rays have high energy
(c) X-rays can penetrate matter	(d) Photons have momentum

Shown in the figure here is a convergent lens placed inside a cell filled with a liquid. The lens has focal length + 20 cm when in air and its material has refractive index 1.50. If the liquid has refractive index 1.60, the focal length of the system is

(a) + 80 cm

(b) – 80 cm

(c) – 24 cm

(d) –100 cm

A capacitor is connected to an A.C. circuit, then the phase difference between current and the voltage is:

The momentum of a photon is 2  gm-cm/sec. Its energy is

(a) 0.61

(b) 2.0

(c) 6

(d) 6

A straight conductor carries a current of 5A. An electron travelling with a speed of 5  parallel to the wire at a distance of 0.1m from the conductor, experiences a force of

(a) 8

(b) 3.2

(c) 8

(d) 1.6

Huygens principle of secondary waves:

The  main source of solar energy is

(a) Fission reactions	(b) Fusion reactions
(c) Chemical reactions	(d) Combustion reactions

The most penetrating radiation out of the following is

(a) X-rays

(b) β -rays

(c) α -  particles

(d) γ - rays

Conventional flow of current will always be from: