Moving Charges and Magnetism — Physics STD 12 Science — Question

Assertion   :   Inductance coil are made of copper.

Reason       : Induced current is more in wire having less resistance.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

A electron (q = 1.6 × 10^–19 C) is moving at right angle to the uniform magnetic field 3.534 × 10^–5 T. The time taken by the electron to complete a circular orbit is

(a) 2 ms

(b) 4 ms

(c) 3 ms

(d) 1 ms

Earth’s potential is _______?

If an electric current is passed through a nerve of a man, then man         

(a) Begins to laugh	(b) Begins to weep
(c) Is excited	(d) Becomes insensitive to pain

Number of spectral lines in hydrogen atom is:

Which of the following electromagnetic waves have minimum frequency

(a) Microwaves

(b) Audible waves

(c) Ultrasonic waves

(d) Radiowaves

The explosion of the atomic bomb takes place due to

(a) Nuclear fission	(b) Nuclear fusion
(c) Scattering	(d) Thermionic emission

Total internal reflection can take place only if:

1. Light goes from optically rarer medium (smaller refractive index) to optically denser medium.
2. Light goes from optically denser medium to rarer medium.
3. The refractive indices of the two media are close to each other.
4. The refractive indices of the two media are widely different.

The splitting of line into groups under the effect of electric or magnetic field is called

(a) Zeeman's effect	(b) Bohr's effect
(c) Heisenberg's effect	(d) Magnetic effect

A bar magnet is released from rest along the axis of a very long, vertical copper tube. After some time the magnet: