LASER Dr A K Srivastava Previous knowledge testing

LASER Dr. A. K. Srivastava

Previous knowledge testing

A LASER Source is A)monochromatic B) bi-chromatic C)white D)None of these

A LASER transition is A) Collisional transition B) Radiative transition C) Thermal transition D) None of these

Which of the following is non-radiative transition A) Stimulated emission B) Collisional transitions C) Spontaneous emission D) Stimulated absorption

Which of the following relations between Einstein A and B coefficients for lower 1 and upper level 2 is correct

In a system three levels A, B and C have energies 0. 5 e. V, 1. 2 e. V and 2. 6 e. V, respectively. The excitation form the lower B to the upper level C can be done by a photon having energy A)1. 2 e. V C) 1. 4 e. V B)2. 6 e. V D) 2. 1 e. V

In He-Ne laser the most favorable ratio of the helium to neon for satisfactory laser action is A) 1: 4 B) 4: 1 C) 1: 7 D) 7: 1 or 10: 1

The number of energy levels used in the He-Ne laser is A) 2 B) 3 C) 4 D) 5

The image produced by holography is A) 1 - dimensional B) 2 - dimensional C) 3 - dimensional D) 4 - dimensional

A hologram contains the information of the object about A) Amplitude only B) Amplitude and phase both C) Phase only D) Neither amplitude nor phase

Hologram is the consequence of A) Interference of object and reference beam B) Polarization of object and reference beam C) Diffraction of object and reference beam D) Both interference and polarization of object and reference beam.

The information carrying capacity of hologram is A) Less than an ordinary photograph B) Equal to an ordinary photograph C) More than an ordinary photograph D) None of these

Laser action is NOT possible when the system has the following number of levels A) 2 B) 3 C) 4 D) 5

The radiative life time of a metastable level is of the order of

Nd- YAG LASER is known as the system of the following number of levels A) 2 B) 3 C) 4 D) 5

END Of The TEST