Modern Physics Mock Test - 2

Question: 6

The materials which conduct electricity at zero resistance are called

(A) superconductors

(B) semiconductors

(C) insulators

(D) conductors

Question: 7

After pumping process in laser, ______

(A) no atoms are available in the excited state

(B) the number of atoms in the ground state is equal to the number of atoms in the excited state

(C) the number of atoms in the ground state is greater than the number of atoms in the excited state

(D) the number of atoms in the excited state is greater than the number of atoms in the ground state

Question: 8

According to Sommerfeld, since the orbit of the electron is elliptical, the velocity of the electron is

(A) minimum when the electron is nearest to the nucleus and maximum when it is farthest from the nucleus

(B) minimum when the electron is nearest to the nucleus or farthest from the nucleus

(C) maximum when the electron is nearest to the nucleus or farthest from the nucleus

(D) maximum when the electron is nearest to the nucleus and minimum when it is farthest from the nucleus

Question: 9

Metastable state in laser is

(A) short lived state of atoms in the ground state

(B) long lived state of atoms in the ground state

(C) short lived state of atoms in the excited state

(D) long lived state of atoms in the excited state

Question: 10

An atom at the ground level is carried to the excited level by photon. It is known as

(A) spontaneous absorption

(B) induced emission

(C) induced radiation

(D) induced absorption