Question # 1

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

Choose an answer

Proton

Positron

Pion

Pi-meson

Both (C) and (D)

In order to produce pair production, a photon must have a energy

Choose an answer

0.511 Me v

0.256 Me v

1.02 Me v

0.956 Me v

In photoelectric effect the energy of ejected electrons depend on

Choose an answer

The frequency

The intensity

Both frequency and intensity

None of these

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

Choose an answer

1.66 x 10^-29m

1.74 x 10^-10cm

17.4 x 10^-6m

1.74 x 10^-10m

A non-inertial frame of reference is one, in which

Choose an answer

law of inertial is valid

all laws of physics are the same in all frames

a>0 or a<0

a=0

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

Choose an answer

Newton

Joule

Joule-Sec

Joule-s^-1

Watt

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

Choose an answer

5.6 x 10⁸Wm^-2K^-4

5.67 x 10^-8Wm^-2K^-4

2.9 x 10^-3mK

2.9 x 10³mK

The special theory of relatively treats the problems involving:

Choose an answer

Inertial frames of reference

Non-inertial frames

Non-accelerated frame

Botha (A) and (C)

Both (B) and (C)

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

Choose an answer

Dilates itself

Contracts itself

Stretches itself

Both (A) and (C)

None of these

According to the special theory of relativity, a moving clock

Choose an answer

runs faster

runs slower

neither runs faster nor slower

all of these

When a platinum wire is heated, it appears yellow at

Choose an answer

1600°C

900°C

1100°C

1300°C

The mass of an object will be doubled at speed

Choose an answer

1.6 x 10⁸ms^-1

2.6 X 10⁸ms^-1

2.6 x 10⁷ms^-1

2.6 x 10⁹ms^-1

Wave nature of particle was proposed by

Choose an answer

Einstein

Plank

De-Brogile

Max well

If a body reaches a speed equal to the speed of light, then its mass will became

Choose an answer

zero

very small

infinity

none of these

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

Choose an answer

classical mechanics

Newtonian mechanics

quantum mechanics

statistical mechanics

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

Choose an answer

Remains constant

Decreases

Increases

Reduces to zero

More Classes

Other Links

ECAT Physics Chapter 19 Dawn of Modern Physics Online Test MCQs With Answers

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer

Choose an answer