ECAT Pre General Science Physics Chapter 19 MCQ Test With Answer

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

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ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics

00:00
Question # 1

The energy of a photon is represented by

Question # 2

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

Question # 3

When platinum wire is heated, then at the temperature of 500 oC, it becomes:

Question # 4

The location and speed anywhere on earth can now be determined using relativistic effects by NAVISTAR to an accuracy of

Question # 5

The length contraction happens only

Question # 6

A particle having mass and charge equal to that of an electron is called:

Question # 7

Which one of the following physical quantities changes with relativistic speed

Question # 8

The energy of a photon in a beam of infrared radiation of wavelength 1240 nm is

Question # 9

If A represents linear momentum and c, the velocity of light, then unit of pc in international system of units is:

Question # 10

When monochromatic light is allowed to fall on cathode, it begins to emit electrons, these electrons are called

Question # 11

At the temperature, a body emits radiation which is principally

Question # 12

the dilation of time applies to the timing processes which are:

Question # 13

The positron was discovered by:

Question # 14

The emission of electrons from a metal surface when exposed to light of suitable frequency is called the

Question # 15

Converse of pair production is known as

Question # 16

When a platinum wire is heated, it appears dull red at about

Question # 17

From the theory of relativity, momentum p of the photon is related to energy as

Question # 18

Photocell is a device which converts

Question # 19

A black body is

Question # 20

Albert Einstein got the Nobel prize in physics for his explanation of photoelectric effect in

Question # 21

Victor de-Brogile received the Nobel prize in physics in

Question # 22

Which of the following phenomenon proves the particle nature of light

Question # 23

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 # 24

When low energy photon interact with a metal,which of the following effect is likely to be taken place

Question # 25

When a position comes close to an electron they annihilate into

Question # 26

There is certain frequency below which no electrons are emitted from the metal surface, this frequency is known as

Question # 27

According to the electromagnetic wave theory of light, increasing the intensity of incident light should increase the

Question # 28

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

Question # 29

The Stephen-Boltzmann law for the black body radiation is given by

Question # 30

Absolute motion cannot be detected

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ECAT Physics Chapter 19 Important MCQ's

Sr.# Question Answer
1 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
2 Wien's constant is measured in:
A. Metre per kelviin
B. Metre kelvin
C. Kelvin per meter
D. Joules
3 An inertial frame is that frame in which
A. a>0
B. a=0
C. a<0
D. none of these
4 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
5 The location and speed anywhere on earth can now be determined using relativistic effects by NAVISTAR to an accuracy of
A. 2 cm/s
B. 20 cm/s
C. 200 cm/s
D. 2000 cm/s
6 Which one of the following physical quantities changes with relativistic speed
A. Length
B. Mass
C. Time
D. All of the above
7 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
8 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:
A. Smaller
B. Lerger
C. Same
D. Much larger
9 Compton was awarded Nobel prize in physics in
A. 1921
B. 1923
C. 1925
D. 1927
10 The value of the Stephen's constant for black body radiations is given by
A. 5.6 x 108Wm-2K-4
B. 5.67 x 10-8Wm-2K-4
C. 2.9 x 10-3mK
D. 2.9 x 103mK

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