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	The value of the plank's constant 'h' is given by	A. 1.6 x 10^-19J B. 1.67 x 10^-27Kg C. 6.63 x 10³⁴Js D. 6.63 x 10^-34Js
2	The inside cavity of the black body is	A. painted white B. painted silver C. blackened with soot D. painted red
3	When monochromatic light is allowed to fall on cathode, it begins to emit electrons, these electrons are called	A. thermoionic electrons B. free electrons C. photoelectrons D. slow electrons
4	When a platinum wire is heated, it appears dull red at about	A. 500°C B. 900°C C. 1100°C D. 1300°C
5	The Stephen-Boltzmann law for the black body radiation is given by	A. E = T² B. E = -T² C. E = T⁴ D. E = -T⁴
6	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
7	When platinum wire is heated, it appears cherry red at	A. 1600°C B. 900°C C. 1100°C D. 1300°C
8	the symbol to be used in relativity problems denotes:	A. Dilated time B. Proper time C. Life time D. Half time
9	If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is:	A. Newton B. Joule C. Joule-Sec D. Joule-s^-1
10	Intensity of light determines the:	A. Energy of each photon B. Number of photons C. Speed of photons D. Size of photons