Moving Charges and Magnetism — Physics STD 12 Science — Question

Biot-Savart law indicates that the moving electrons (velocity v) produce a magnetic field B such that:

Two streams of electrons are moving parallel to each other in the same direction. They_____.

The specific heat capacity of a body depends on:

1. The heat give.
2. The temperature raised.
3. The mass of the body.
4. The material of the body.

Two short magnets of equal dipole moments M are fastened perpendicularly at their centre (figure). The magnitude of the magnetic field at a distance d from the centre on the bisector of the right angle is:

An endoscope is employed by a physician to view the internal parts of a body organ. It is based on the principle of

(a) Refraction	(b) Reflection
(c) Total internal reflectionn	(d) Dispersion

In a beryllium atom, if a₀ be the radius of the first orbit, then the radius of the second orbit will be in general

(a)

(b)

(c)

(d)

The maximum value of stopping potential in the following diagram is

(a) – 4V

(b) – 1V

(c) – 3V

(d) – 2V

Cathode rays are group of :

An antenna is a device

(a) That converts electromagnetic energy into radio frequency signal

(b) That converts radio frequency signal into electromagnetic energy

(c) That converts guided electromagnetic waves into free space electromagnetic waves and vice-versa

(d) None of these

Hydrogen atom emits blue light when it changes from n = 4 energy level to the n = 2 level. Which colour of light would the atom emit when it changes from the n = 5 level to the n = 2 level

(a) Red

(b) Yellow

(c) Green

(d) Violet