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

In photoelectric effect, the stopping potential (V0) v/s frequency ( ) curve is plotted. ( h is the Planck's constant and 0 is work function of metal ) Choose the correct answer from the options given below :

1. (A), (C) and (E) only
2. (C) and (D) only
3. (A), (B) and (C) only
4. (D) and (E) only

In photoelectric effect an em-wave is incident on a metal surface and electrons are ejected from the surface. If the work function of the metal is 2.14 eV and stopping potential is 2 V, what is the wavelength of the em-wave? (Given hc=1242 eV nm where h is the Planck's constant and c is the speed of light in vacuum.)

1. 400 nm
2. 600 nm
3. 300 nm
4. 200 nm

The work functions of cesium (Cs) and lithium (Li) metals are 1.9 eV and 2.5 eV , respectively. If we incident a light of wavelength 550 nm on these two metal surfaces, then photo-electric effect is possible for the case of

1. Both Cs and Li
2. Neither Cs nor Li
3. Li only
4. Cs only

A light source of wavelength illuminates a metal surface and electrons are ejected with maximum kinetic energy of 2 eV . If the same surface is illuminated by a light source of wavelength 2, then the maximum kinetic energy of ejected electrons will be (The work function of metal is 1 eV )

1. 5 eV
2. 3 eV
3. 2 eV
4. 6 eV

UV light of 4.13 eV is incident on a photosensitive metal surface having work function 3.13 eV. The maximum kinetic energy of ejected photoelectrons will be:

1. 4.13 eV
2. 1 eV
3. 7.26 eV
4. 3.13 eV

Which of the following phenomena is not explained by wave nature of light? Choose the most appropriate answer from the options given below:

1. C only
2. B, D only
3. A, C only
4. E only

In photoelectric experiment energy of 2.48 eV irradiates a photo sensitive material. The stopping potential was measured to be 0.5 V. Work function of the photo sensitive material is :

1. 1.98 eV
2. 1.68 eV
3. 2.48 eV
4. 0.5 eV

When UV light of wavelength 300 nm is incident on the metal surface having work function 2.13 eV, electron emission takes place. The stopping potential is : (Given hc = 1240 eV nm)

1. 4 V
2. 2 V
3. 4.1 V
4. 1.5 V

Given below are two statements : [figure] In the light of the above statements, choose the most appropriate answer from the options given below.

1. Statement I is correct and Statement II is incorrect
2. Statement I is incorrect but Statement II is correct
3. Both Statement I and Statement II are correct
4. Both Statement I and Statement II are incorrect

Which of the following statement is not true about stopping potential (V0) ?

1. It depends upon frequency of the incident light.
2. It is 1/e times the maximum kinetic energy of electrons emitted.
3. It increases with increase in intensity of the incident light.
4. It depends on the nature of emitter material.

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. In the light of the above statements, choose the most appropriate answer from the options given below:

1. A is not correct but R is correct.
2. A is correct but R is not correct.
3. Both A and R are correct and R is the correct explanation of A.
4. Both A and R are correct and R is NOT the correct explanation of A.

When a metal surface is illuminated by light of wavelength , the stopping potential is 8 V. When the same surface is illuminated by light of wavelength 3 , stopping potential is 2 V. The threshold wavelength for this surface is:

1. 3
2. 9
3. 5
4. 4.5

The work function of a substance is 3.0 eV. The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately;

1. 215 nm
2. 400 nm
3. 414 nm
4. 200 nm

For the photoelectric effect, the maximum kinetic energy (Ek) of the photoelectrons is plotted against the frequency ( ) of the incident photons as shown in figure. The slope of the graph gives [figure]

1. Planck's constant
2. Work function of the metal
3. Charge of electron
4. Ratio of Planck's constant to electric charge