ECAT Pre General Science Chapter 19 online mcq test with answers for Physics chapter 19 (Dawn of Modern Physics)

Question # 1

Which of the following is not an example of intertial frame

a body placed on the surface of earth A
a body placed in a car moving with uniform velocity B
a body placed in a car moving with same acceleration C
none of these D

Question # 2

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

Newton A
Joule B
Joule-Sec C
Joule-s^-1 D
Watt E

Question # 3

An intertial frame of reference is a frame of reference which is

at rest A
moving with uniform velocity B
either at rest or moving with uniform velocity C
none of these D

Question # 4

According to the special theory of relativity, a moving clock

runs faster A
runs slower B
neither runs faster nor slower C
all of these D

Question # 5

Max plank founded a mathematical model resulting in an equation that describes the shape of observed black body radiation curves exactly, in

1890 A
1895 B
1900 C
1905 D

Question # 6

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

100 ev A
10⁶e v B
10³e v C
1.0 e v D

Question # 7

The length contraction happens only

Opposite to the direction of motion A
along the direction of motion B
perpendicular to the direction of motion C
In any direction D

Question # 8

Current, voltage, resistance measuring circuit is connected with the galvanometer with the help of switch, known as

ON switch A
off switch B
function switch C
none of these D

Question # 9

Which one of the following physical quantities changes with relativistic speed

Length A
Mass B
Time C
All of the above D

Question # 10

The positron was discovered by:

In cosmic radiation A
In 1932 B
By Carl Anderson C
All above D
By direc E

Question # 11

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

1916 A
1919 B
1921 C
1923 D

Question # 12

The stopping voltage for a certain metal is 100 volts, then the work function for the cathode plate is

100 J A
1.6 x 10^-17J B
100 eV C
1.6 x 10^-17eV D

Question # 13

Wien's constant is measured in:

Metre per kelviin A
Metre kelvin B
Kelvin per meter C
Joules D
Dynes E

Question # 14

G.P. Thomson observer experimentally that electrons and neutrons possess

particle-like properties A
wave-like properties B
neither particle nor wave like properties C
none of these D

Question # 15

The concept of direction and position are purely

absolute A
relative B
absolute or relative C
none of these D

Question # 16

Converse of pair production is known as

Compton effect A
annihilation of matter B
photoelectric effect C
none of these D

Question # 17

The value of threshold frequency for different metals is

different A
same B
may be different or may be same C
none of these D

Question # 18

In process of annihilation of matter, the two photons produced move in opposite direction to converse

momentum A
charge B
energy C
mass D

Question # 19

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

Physical A
Chemical B
Biological C
All of these D
None of these E

Question # 20

An inertial frame is that frame in which

a>0 A
a=0 B
a<0 C
none of these D

Question # 21

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

number of photoelectrons A
size of the photoelectrons B
charge on photoelectrons C
K.E of photoelectrons D

Question # 22

The special theory of relativity is based on:

Four postulates A
Three postulates B
Two postulates C
One postulate D
None of these E

Question # 23

The nature of radiations emitted by a hot body depends upon its:

Metarial A
Temperature B
colour C
Volume D
Length E

Question # 24

Due to relative motion of observer and the frame of reference of events, time always:

Dilates itself A
Contracts itself B
Stretches itself C
Both (A) and (C) D
None of these E

Question # 25

The inside cavity of the black body is

painted white A
painted silver B
blackened with soot C
painted red D

Question # 26

If the radius of first orbit of hydrogen atom is 0.53° A the radius of second orbit will be

2.120°A A
0.212°A B
21.2°A C
0.14°
a
D

Question # 27

The general theory of relativity treats problems involving

inertial frame of references A
accelerating frame of references B
both of these C
none of these D

Question # 28

According to the special theory of relativity, time is

absolute quantity A
not absolute quantity B
constant quantity C
none of these D

Question # 29

Compton derived an expression to find compton shift by applying to the process, the law of conservation of:

Energy only A
Momentum only B
Mass only C
Charge only D
Both (A) and (B) E

Question # 30

At the temperature, a body emits radiation which is principally

of long wavelengths in the visible region A
of long wavelengths in the invisible infrared region B
of short wavelength in invisible ultraviolet region C
none of these D

Sr.#	Question	Answer
1	At the temperature, a body emits radiation which is principally	A. of long wavelengths in the visible region B. of long wavelengths in the invisible infrared region C. of short wavelength in invisible ultraviolet region D. none of these
2	Strictly speaking, the earth is:	A. An accelerated frame of reference B. A non-inertial frame of reference C. An inertial frame of reference D. ^{A non-accelerated frame of reference}
3	The nature of radiations emitted by a hot body depends upon its:	A. Metarial B. Temperature C. colour D. Volume
4	Compton shift refers to:	A. Photon B. Meson C. Proton D. Positron
5	According to the special theory of relativity, time is	A. absolute quantity B. not absolute quantity C. constant quantity D. none of these
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	The threshold frequency of sodium is 6 x 10⁶MHz. The cut-off wavelength for this metal will be	A. 500 m B. 500 nm C. 500 km D. 500 cm
8	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
9	Max plank founded a mathematical model resulting in an equation that describes the shape of observed black body radiation curves exactly, in	A. 1890 B. 1895 C. 1900 D. 1905
10	If you are moving at relativistic speed between two points that are a fixed distance apart, then the distance between the two points appers	A. larger B. shorter C. equal D. none of these

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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

ECAT Pre General Science Physics Chapter 19 Dawn of Modern Physics