ECAT Pre Engineering Physics Chapter 19 MCQ Test With Answer

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

Sr.#	Question	Answer
1	Which one of the following physical quantities changes with relativistic speed	A. Length B. Mass C. Time D. All of the above
2	Electromagnetic -radiation means:	A. Photons B. protons C. Electrons D. Mesons
3	Converse of pair production is known as	A. Compton effect B. annihilation of matter C. photoelectric effect D. none of these
4	A bar 1.0 m in length and located along x-axix moves with a speed of 0.75 c with respect to a stationary observer. The length of the bar as measured by the stationary observer is	A. 1.66 m B. 1.0 m C. 0.66 m D. 2.66 m
5	S.I. unit of planks constant is	A. J-s^-1 B. J.s C. J.s^-2 D. J.s²
6	The whole shape of the black body spectrum for all wavelengths was explained by the formula proposed by	A. Max plank B. Newton C. Einstein D. J.J. Thomson
7	When a platinum wire is heated, it appears white at	A. 1600°C B. 900°C C. 1100°C D. 1300°C
8	The length contraction happens only	A. Opposite to the direction of motion B. along the direction of motion C. perpendicular to the direction of motion D. In any direction
9	The speed of a pendulum is measured to be 3.0 s in the inertial reference frame of the pendulum. What is its period measured by an observer moving at a speed of 0.95 c with respect to the pendulum	A. 2.9 s B. 3.0 s C. 6.6 s D. 9.6 s
10	Max Planck received the Nobel Prize for his discovery of energy quants in:	A. 1718 AD B. 1918 AH C. 1818 AD D. 1918 AD