Dual Nature of Radiation and Matter

K1 and K2 be the maximum kinetic energies of photoelectrons emitted from a surface of a given material for the light of wavelength 1 and 2, respectively. If 1=2 2 then the work function of material is given by :

1. K2+2K1
2. 2K2-K1
3. K1-2K2
4. K2-2K1

Light source having wavelength 331 nm is used to generate photo-electrons whose stopping potential is 0.2 V. The work function of the used metal in the experiment is 10-19 J. The value of is . (h=6.62 10-34 J s, e=1.6 10-19 C and c=3 108 m/s)

1. 3.68
2. 4.68
3. 5.68
4. 2.68

For a certain metal, when monochromatic light of wavelength is incident, the stopping potential for photoelectrons is 3V0. When the same metal is illuminated by light of wavelength 2 , then the stopping potential becomes V0. The threshold wavelength for photoelectric emission for the given metal is . The value of is .

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

When a light of a given wavelength falls on a metallic surface the stopping potential for photoelectrons is 3.2 V. If a second light having wavelength twice of first light is used, the stopping potential drops to 0.7 V. The wavelength of first light is m. (h = 6.63 10-34 J s, e = 1.6 10-19 C, c = 3 108 m/s)

1. 2.9 10-8
2. 2.5 10-7
3. 3.1 10-7
4. 2.2 10-8

Light is incident on a metallic plate having work function 110 10-20 J. If the produced photoelectrons have zero kinetic energy then the angular frequency of the incident light is rad/s. (h = 6.63 10-34 J s)

1. 1.04 1013
2. 1.66 1016
3. 1.66 1015
4. 1.04 1016

A light wave described by E = 60 [ (3 1015 t ) + (12 1015 t ) ] (in SI units) falls on a metal surface of work function 2.8 eV. The maximum kinetic energy of ejected photoelectron is (approximately) eV. (h = 6.6 10-34 J s and e = 1.6 10-19 C)

1. 3.8
2. 7.8
3. 6.0
4. 5.1

The work function of a metal is 3 eV. The color of the visible light that is required to cause emission of photoelectrons is

1. Red
2. Green
3. Blue
4. Yellow

Which of the following phenomena cannot be explained by wave theory of light?

1. Refraction of light
2. Reflection of light
3. Diffraction of light
4. Compton effect