ECAT Pre Computer Science Chapter 19 MCQ Test With Answer

Top Scorers Of ECAT Physics Chapter 19 Dawn of Modern Physics MCQ`s Test

Sr.#	Question	Answer
1	The value of threshold frequency for different metals is	A. different B. same C. may be different or may be same D. none of these
2	When the atomic particle are moving with velocities approaching that of light:	A. Newton's laws become valid B. Relativistic effects become prominent C. Botha(A) and (B) are valid D. Neither (A)nor (B)
3	Compton studied the scattering of x-rays by loosely bound electrons from:	A. NaCl crystal B. Graphite crystal C. Zirconia D. Copper crystal
4	When a platinum wire is heated, it appears yellow at	A. 1600°C B. 900°C C. 1100°C D. 1300°C
5	Which of the following is not an example of intertial frame	A. a body placed on the surface of earth B. a body placed in a car moving with uniform velocity C. a body placed in a car moving with same acceleration D. none of these
6	When a position comes close to an electron they annihilate into photons such that	A. each photon has energy 0.51 Me v B. each photon has energy 1.02 Me v C. each photon has energy 0.25 Me v D. none of these
7	As the light shines on the metal surface, the electrons are ejected	A. slowly B. instantaneously C. either of these D. none of these
8	A black body is	A. an ideal absorber B. an ideal radiator C. both of them D. none of them
9	The unit of work function is:	A. Joule B. Electron volt C. That of threshold frequency D. Both (A) and (B)
10	In order to produce pair production, a photon must have a energy	A. 0.511 Me v B. 0.256 Me v C. 1.02 Me v D. 0.956 Me v