Dual Nature of Radiation and Matter · Question 25

The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (kelvin) and mass m, is

1. h 3mkT
2. 2h 3mkT
3. 2h mkT
4. h mkT

The photoelectric threshold wavelength of silver is 3250 10-10 m. The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength 2536 10-10 m is [Given h = 4.14 10-15 eV s and c = 3 108 m s-1]

1. 0.6 106 m s-1
2. 61 103 m s-1
3. 0.3 106 m s-1
4. 6 105 m s-1

An electron of mass m and a photon have same energy E. The ratio of de-Broglie wavelengths associated with them is

1. c(2mE) 12
2. 1c ( 2mE ) 12
3. 1c ( E2m ) 12
4. ( E2m ) 12

When a metallic surface is illuminated with radiation of wavelength , the stopping potential is V. If the same surface is illuminated with radiation of wavelength 2 , the stopping potential is V4. The threshold wavelength for the metallic surface is

1. 52
2. 3
3. 4
4. 5

Photons with energy 5 eV are incident on a cathode C in a photoelectric cell. The maximum energy of emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach the anode A, if the stopping potential of A relative to C is

1. +3 V
2. +4 V
3. -1 V
4. -3 V

A photoelectric surface is illuminated successively by monochromatic light of wavelength and /2. If the maximum kinetic energy of the emitted photoelectrons in the second case is 3 times that in the first case, the work function of the surface of the material is (h = Planck's constant, c = speed of light)

1. 2hc
2. hc3
3. hc2
4. hc

Light of wavelength 500 nm is incident on a metal with work function 2.28 eV. The de Broglie wavelength of the emitted electron is

1. 2.8 10-9 m
2. 2.8 10-12 m
3. < 2.8 10-10 m
4. < 2.8 10-9 m

Which of the following figures represent the variation of particle momentum and the associated de-Broglie wavelength?

1. [figure]
2. [figure]
3. [figure]
4. [figure]

A certain metallic surface is illuminated with monochromatic light of wavelength, . The stopping potential for photo-electric current for this light is 3V0. If the same surface is illuminated with light of wavelength 2 , the stopping potential is V0. The threshold wavelength for this surface for photo-electric effect is

1. 4
2. 6
3. 6
4. 4

When the energy of the incident radiation is increased by 20%, the kinetic energy of the photoelectrons emitted from a metal surface increased from 0.5 eV to 0.8 eV. The work function of the metal is

1. 0.65 eV
2. 1.0 eV
3. 1.3 eV
4. 1.5 eV