Sr. No.

Marks

Section – A

All questions are compulsory. In case of internal choices, attempt any one of them.

1

Name the physical quantity having unit J/T.

1

2

Mention one use of part of electromagnetic spectrum to which a wavelength

of 21 cm (emitted by hydrogen in interstellar space) belongs.

OR

Give the ratio of velocity of the two light waves of wavelengths 4000Å and 8000Å travelling in vacuum.

1

3

An electron with charge -e and mass m travels at a speed v in a plane

perpendicular to a magnetic field of magnitude B. The electron follows a circular path of radius R. In a time, t, the electron travels halfway around the circle. What is the amount of work done by the magnetic field?

1

4

A solenoid with N loops of wire tightly wrapped around an iron-core is

carrying an electric current I. If the current through this solenoid is reduced to half, then what change would you expect in inductance L of the solenoid.

OR

An alternating current from a source is given by i=10sin314t.  What is the effective value of current and frequency of source?

1

5

What is the value of angular momentum of electron in the second orbit of

Bohr’s model of hydrogen atom?

1

6

In a photoelectric experiment, the potential required to stop the ejection of

electrons from cathode is 4V. What is the value of maximum kinetic energy of emitted Photoelectrons?

1