Second Year Physics Chapter 19 Online MCQ Test for 2nd Year Physics Chapter 19 Dawn of Modern Physics Preparation

A block body is an ideal:

• Absorber A
• Radiator B
• Both a & b C
• None of above D

A perfect absorber must also be perfect

• Cavity A
• Sources of radiation B
• Radiator C
• None of these D

In the equation if f₂ > then

• 
  A
• 
  B
• 
  C
• 
  D

Pair production cannto take place in vacuum because :

• Mass in not conserved A
• Momentum is not conserved B
• Energy is not conserved C
• Charge is not conserved D

De-Broglie waves are associated with

• Moving charged particles only A
• Moving neutral particles only B
• All moving particles C
• All parties whether in motion or at rest D

Wave nature of particle was given by:

• Clemensen A
• Louis de Broglie B
• Laster H. Germer C
• Clinton S. Davisson D

Photo electrons are emitted y using visible light when the metal is.

• sodium A
• Copper B
• Nicked C
• Cobalt D

The photoelectric effect predicts that light is made of

• Photons A
• Neutrons B
• Protons C
• None of these D

Pair production occurs only when energy of photon is at least equal in:

• 1.02keV A
• 1.02 eV B
• 1.02 MeV C
• 1.02 GeV D

Platinum wire becomes yellow at a temperature of.

• 900 ^oC A
• 1300^oC B
• 1600^oC C
• 500^oC D

The minimum frequency needed to emit an electron form metal surface is called:

• Work function A
• Threshold frequency B
• Quanta frequency C
• All of above D

If an object moves with speed of light, its mass will be.

• Zero A
• Maximum B
• Minimum C
• infinity D

Max planck received noble prize in:

• 1927 A
• 1932 B
• 1918 C
• 1914 D

Pair production can take place only when energy of radiation is equal and greater than 1.02 MeV, thus correct option is.

• X rays A
• Gama rays B
• Heat Radiation C
• Ultraviolet rays D

The maximum kinetic energy of emitted photo electrons depends upon.

• The intensity of incident light A
• Frequency of the incident light B
• Metal surface C
• Both frequency of incident light and metal surface. D

• Wien's constant A
• Planck's constant B
• Davison constant C
• Lumber's constant D

The existence of positron was discovered in:

• 1929 A
• 1928 B
• 1931 C
• 1933 D