ECAT Pre Computer Science Chapter 19 MCQ Test With Answer

MCQ's Test For ECAT Physics Chapter 19 Dawn of Modern Physics

Try The MCQ's Test For ECAT Physics Chapter 19 Dawn of Modern Physics

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ECAT Physics Chapter 19 Dawn of Modern Physics

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Question # 1

The value of the Stephen's constant for black body radiations is given by

Question # 2

The special theory of relativity treats problems invoving

Question # 3

As compared to the distance measured by an observer on Earth, the distance from Earth to a star measured by an observer in a moving spaceship would seem:

Question # 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

Question # 5

An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is

Question # 6

Electromagnetic radiation or photons interact with matter in

Question # 7

The special theory of relativity is based on:

Question # 8

The threshold frequency of sodium is 6 x 106MHz. The cut-off wavelength for this metal will be

Question # 9

The Nobel Prize on the explanation of photoelectric effect was awarded to:

Question # 10

The analysis of the distribution of wavelengths of the radiation emitted from a hot body set the foundation of new mechanics, known as

Question # 11

The energy of photon 'E' is proported to

Question # 12

According to Einstein, with the great increase in the speed of the body, the relativistic mass of the body

Question # 13

The Einstein's changes in length, mass and time are not observed in common life because

Question # 14

When a platinum wire is heated, it appears white at

Question # 15

Absolute motion cannot be detected

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ECAT Physics Chapter 19 Important MCQ's

Sr.# Question Answer
1 Wien's constant is measured in:
A. Metre per kelviin
B. Metre kelvin
C. Kelvin per meter
D. Joules
2 The intensity of emitted energy (with wavelength) radiated from a black body at different temperatures was initially measured by:
A. Lummer
B. Planck
C. Pringsheim
D. Both (A ) and (B)
3 According to the Max plank, energy is redialed or absorbed in
A. discrete packets
B. continuous waves
C. either of them
D. none of these
4 Electromagnetic -radiation means:
A. Photons
B. protons
C. Electrons
D. Mesons
5 Photocell is a device which converts
A. chemical energy into electrical energy
B. electrical energy into light energy
C. heat energy into electrical energy
D. light energy into electrical energy
6 According to the special theory of relativity, a moving clock
A. runs faster
B. runs slower
C. neither runs faster nor slower
D. all of these
7 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
8 When a position comes close to an electron they annihilate into
A. one photon
B. two photons which travel in the same direction
C. two photons which travels in the opposite direction
D. two photons which travel in any direction
9 An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is
A. 1.66 x 10-29m
B. 1.74 x 10-10cm
C. 17.4 x 10-6m
D. 1.74 x 10-10m
10 If the radius of first orbit of hydrogen atom is 0.53° A the radius of second orbit will be
A. 2.120°A
B. 0.212°A
C. 21.2°A
D. 0.14°
a

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