Question # 1

Practically the quantity v/c is always:

Choose an answer

less than one

Equal to one

Greater then one

all of these

None of these

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

Intensity of light determines the:

Choose an answer

Energy of each photon

Number of photons

Speed of photons

Size of photons

None of these

According to the special theory of relativity, time is

Choose an answer

absolute quantity

not absolute quantity

constant quantity

none of these

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

Choose an answer

pair production

Compton effect

photoelectric effect

relativity

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

Choose an answer

We dont observer then seriously

The masses are too large

Their speed is too small than the speed of right

All of the above

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

Choose an answer

Remains constant

Decreases

Increases to infinity

Reduced to zero

The general theory of relativity treats problems involving

Choose an answer

inertial frame of references

accelerating frame of references

both of these

none of these

The mass 'm' of a body moving at 0.8 c (whose rest mass is mo) becomes

Choose an answer

2 mo

1.67 mo

0.67 mo

2.67 mo

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

Choose an answer

Yellow

Orange red

Dull red

White

Cherry red

Which of the following phenomenon proves the particle nature of light

Choose an answer

interference

diffraction

photoelectric effect

none of these

Photoelectric effect takes place with a photon of:

Choose an answer

Very high energy

Very low energy

Low energy

High energy

None of these

The intensity of emitted energy (with wavelength) radiated from a black body at different temperatures was initially measured by:

Choose an answer

Lummer

Planck

Pringsheim

Both (A ) and (B)

Both (A) and (C)

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

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

Choose an answer

100 ev

10⁶e v

10³e v

1.0 e 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

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

Wave nature of particle was proposed by

Choose an answer

Einstein

Plank

De-Brogile

Max well

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:

Choose an answer

Smaller

Lerger

Same

Much larger

None of these

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

Choose an answer

number of photoelectrons

size of the photoelectrons

charge on photoelectrons

K.E of photoelectrons

Electromagnetic -radiation means:

Choose an answer

Photons

protons

Electrons

Mesons

None of these

When a platinum wire is heated, it appears yellow at

Choose an answer

1600°C

900°C

1100°C

1300°C

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

The energy of the 4th orbit in hydrogen atom is

Choose an answer

2.5 ev

- 3.5 ev

-0.85 ev

-13.6 ev

Photoelectrons are emitted when ultraviolet light falls on:

Choose an answer

Casium

Silver

Potassium

Any of these

None of these

When a platinum wire is heated, it appears white at

Choose an answer

1600°C

900°C

1100°C

1300°C

The special theory of relativity is based on:

Choose an answer

Four postulates

Three postulates

Two postulates

One postulate

None of these

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

Choose an answer

ON switch

off switch

function switch

none of these

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)

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

Choose an answer

500 m

500 nm

500 km

500 cm

None of these

The photoelectric effect, the maximum energy of photoelectrons depends on the

Choose an answer

particular metal surface

frequency of incident light

both of them

none of them

More Classes

Other Links

ECAT Pre General Science 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

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