mcqs of physics 1st year

Q.1 In Helium Neon laser, population inversion of _________ atoms is achieved which emit
radiations, when they are stimulated to fall at lower level.
A) Neon                                    C) Helium and Neon
B) Helium                                  D) Chromium
Q.2 Wavelength of X-rays is the order of:
A) 10^-6 m                                  C) 10-¹³ m
B) 10^-10 m                                  D) 100 m
Q.3 Laser beam can be used to generate three-dimensional image of object in a process called:
A) Computed technology                                    C) Holography

B) Computed tomography                              D) Computerized axial tomography

Q.4      Which of the following is true for Lasers?

A) Electrons are emitted                                 C) Coherent monochromatic light is emitted
B) Stimulated emission of electrons is needed     D) There is a population inversion of photons
Q.5 What is meant by spontaneous emission of electrons in solids?
A) Electrons being emitted by the solids through photoelectric effect when irradiated with electromagnetic
radiation
B) Incident electrons colliding with electrons in solids and releasing doubling the number of incident electrons
C) Electrons in solids are emitted without any external stimulus through radiation
D) Excited electrons going back to lower energy states immediately by releasing energy.

Q.7 The characteristic X­ray spectrum is due to:
A) The absorption of neutrons by target material C) The bombardment of target material by electrons
B) The bombardment of target material by protons D) The bombardment of target material by alpha particles