12th Class PHYSICS MCQs CHAPTER NO.8 DAWN OF MODERN PHYSICS Test No.1

At what angle, the Compton shift '&inc;λ' equals the Compton wavelength?

A positron is a antiparticle of

Radiations are always emitted or absorbed in the form of packets of energy. This is the statement of

When a platinum wire is heated, at 1600^°ree;C it becomes

The maximum energy of the photoelectrons can be determined by making the

The numerical value of Compton wavelength h/m_°ree;c is equal to

In the wien's displacement law i.e. λ_m x T = constant, the value of constant is

According to special theory of relativity, all laws of physics are same in all

The earth's orbital speed is only

The process in which energy is converted into meter is called

When a very high energy photon interact with a matter, then the following phenomenon taken place

An human eye can detect the electormegnetic radiations of the type

The minimum energy required by a photon to create a electron-positron pair is

A frameof reference in which law of inertia is valid is known as

The pair production and annihilation of matter are

Absolute motion of a body

A coordinate system relative to which measurement are taken is known as

The energy of a photon is given by

The mass of an object will be doulbed at speed

A frame of reference which remains at rest or moves with uniform velocity is called

A.H. Compton studied the X-rays by loosely bound electrons from a graphite target in

The rest mass energy of an electron is

The branch of physics which deals with the behaviour of microscopic particles moving with speed of light is called

In the process of annihilation of matter, the two photons produced move in opposite directino to conserve

If the speed of light becomes infinite, then the mass of electron moving with velocity 3 x 10⁸ m/s becomes [m₀ it the rest mass of electron]

The mass m of a body moving at 0.8 C becomes

In photoelectric effect, light exhibits

Assuming you radiate as does a black body at a temperature about 17^°ree;C, the wavelength of the emitted radiation is

The value of Stefen's constant is

Positron was discovered by Carl Anderson in

Phenomena such as black body radiation , photoelectric effect, the emission of sharp spectral lines by atoms in a gas discharge tube were explained by

Wien's theory explains energy distributon in black body for

A beam of red light and a beam of blue light have exactly the same energy. Which beam contains the greater number of photons?

The relativistic change in mass, length and time in daily life are not observed because

An expression for Compton shift &inc;&lambda for angle θ is given as

The angle of scattering for which the Compton shift is maximum is

In an expression for time dilation, the quantity √1-v²/c²is always

The nature of radiation emitted by a body depends upon

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

According to Max Plank, energy is released or absorbed in discrete packets called

The number of photoelectrons emitted (or photoelectric current) is directly proportional to the

In a photocell, sodium and potassium emit electrons for

The part of theory of relativity which deals with inertial or non-accelerating frames of reference is known as

The velocity at which the relativistic length of a body reduces to half of its original length is

Photoelectric effect was discovered by

The special theory of relativity is based

Max Plank suggested that energy is released or absorbed in discrete packets in

The discrete nature of radiation was introduced by

In Compton effect, the wavelength of the scattered photon as compard to the wavelength of incident X-rays is

The Einstein-energy mass relation can be expressed as

In annihilation of matter, positron and electron pair disappears into two

The theory of relativity which deals with non-inertial frame of reference is called

0.1 kg mass will be equivalent to the energy

The photoelectric effect can be explained by

The process of pair production takes place if the energy of photon is at least

A black body is that which aborbs

Photo electric effect is the converse process of

A device based on photoelectric effect is called

If a material object moves with speed of light, its mass becomes

Modern physics mainly based upon

An intertial frame of reference is that for which

If the temperature of a black body is doubled, the total radiation from the body becomes

In a photocell, certainmetals emit electrons for

For Pair production minimum energy of photon must be

The special theory of relativity is applicable to the objects moving with

The photoelectric effect can be explained on the basis of

The rest mass of a photon is

When the K.E._max of photoelectron is zero, the frequency of incident photon is______that of threshold frequency

Absorption power of perfect black body is

The momentum of a photon frequency f is

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

In photoelectric effect, emitted electrons are called

The length of an object or distance between two points measured by an observer who is relatively at rest is called

A non-inertial frame of reference is that which

The pair production equation can be written as

For an electron or positron, the rest-mass energy is equal to

A photon is considered to have

When the temprature of the body is increased, the radiation becomes richer in

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

In Compton shift, the factor h/m_°ree;c is known as

A high temperature, a body generally emits radiations of

The theory of relativity was proposed by

When a platinum wire is heated, it appears orange at about

If speed of light were infinity, then moving mass m becomes

If we are strictly speaking, then earth is

A particle and its antiparticle, together at one place

In a photcell, cesium coated oxidized silver emits electrons for

Which photon, red, green, or blue carries the most energy?

All motions are

Pair production can take place by using

Compton effect makes use of law of conservation of

The stopping potential (V_°ree;) in photoelectric effect depends on the

In photoelectric effect, if intensity of incident radiation is increased, then there is increase in

The speed of light in free space is

The length contraction happens only

A particle with rest mass 'm_°ree;' and relativistic mass 'm' has kinetic energy equal to

The name of photon for a quantum of light energy was first introduced by

According to special theory of relativity, time is

Black body energy distribution curves are the graphs between

The dimensions of Plank's constant h are same as that of

The phenomenon which proves Einstein's relation (E = mc²) is

Photocell is a device which converts

Special theory of relativity was given in

Black bodies are formed of

If an object moves with a velocity of light, then the apparent length of the object along the direction of motion becomes

The momentum of a photon is

The maximum energy of the photoelectrons is given by the equation

The value of Plank's constant h is given by

The maximum kinetic energy of emitted photoelectrons depends upon

Energy of asingle quanta of elctromagnetic radiation is given the name

he photoelectric effect was explained by

In Compton effect, it was considered that X-rays consist of

When a platinum wire is heated, it appears white at about

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

Pair production confirms the

The speed of photon as compared with the speed of light is always

The classical physics is based upon the laws of

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

The anti matter theory was proposed by

Einstein s photo electric equation is given by

At high temperature, the proprtion of shorter wavelength radiation

Which of the following radiations has photons of maximum energy