Moving Charges and Magnetism — Physics STD 12 Science — Question

Which among the following has a relative permeability much larger than 1?

The colour of bright fringes nearest to the central achromatic fringe in the interference pattern with white light will be:

For the nuclie with mass number > 100:

The resistivity of iron is 1 . The resistance of a iron wire of particular length and thickness is 1 ohm. If the length and the diameter of wire both are doubled, then the resistivity in ohm - m  will be

(a)

(b) 2

(c) 4

(d) 8

According to Maxwell’s hypothesis, a changing electric field gives rise to

(a) An e.m.f.

(b) Electric current

(c) Magnetic field

(d) Pressure radiant

Which impurity is doped in Si to form N-type semi-conductor?

(a) Al

(b) B

(c) As

(d) None of these

Kinetic energy with which the electrons are emitted from the metal surface due to photoelectric effect is

(a) Independent of the intensity of illumination

(b) Independent of the frequency of light

(c) Inversely proportional to the intensity of illumination

(d) Directly proportional to the intensity of illumination

The radius of the nucleus is smaller than the radius of the atom, approximately :

In the above question, potential difference across the 40Ω resistance will be

(a) Zero

(b) 80 V

(c) 40 V

(d) 120 V

The mass of a neutron is the same as that of

(a) A proton

(b) A meson

(c) An epsilon

(d) An electron