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Photoelectric Effect - Multiple Choice Questions

Q1. The intensity of a monochromatic light source is increased. Which of the following is correct?
Energy of an emitted photon
Number of photons emitted per second
A
increases
increases
B
increases
unchanged
C
unchanged
increases
D
unchanged
unchanged

 

Q2. A beam of light of wavelength λ is incident on a clean metal surface and photoelectrons are emitted.

The wavelength of the light is halved but energy incident per second is kept the same.

Which row in the table is correct?

Maximum kinetic energy of the emitted photoelectrons
Number of photoelectrons emitted per second
A
Increases
Unchanged
B
Decreases
Increases
C
Increases
Decreases
D
Decreases
Unchanged

 

Q3. Photons of wavelength 290 nm are incident on a metal plate.

The work function of the metal is 4.1 eV

What is the maximum kinetic energy of the emitted electrons?

A

0.19 eV

B

4.3 eV
C

6.9 eV
D

8.4 eV

 

Q4. When light of a certain frequency greater than the threshold frequency of a metal is directed at the metal, photoelectrons are emitted from the surface.

The power of the light incident on the metal surface is doubled.

Which row shows the effect on the maximum kinetic energy and the number of photoelectrons emitted per second?

Maximum kinetic energy
Number of photoelectrons emitted per second
A
remains unchanged

remains unchanged
B
doubles

remains unchanged
C
remains unchanged

doubles
D
doubles

doubles

 

Q5. Line X on the graphs below shows how the maximum kinetic energy of emitted photoelectrons varies with the frequency of incident radiation for a particular metal.

Which graph shows the results for a metal Y that has a higher work function than X?