Photoelectric Effect

Electromagnetic radiation incident on a metal surface can cause electrons to be emitted.

Which of the following statements is correct?

• Every photon incident on the surface causes an electron to be emitted.

• All the emitted electrons have the same energy.

• The range of energy of the emitted electrons depends on the intensity of the radiation.

• If the incident radiation is of a single frequency, the number of electrons emitted per second increases if the intensity of the radiation increases.

In a photoelectric experiment, light is incident on the metal surface of a photocell. Increasing the intensity of the illumination at the surface leads to an increase in the:

• work function

• minimum frequency at which electrons are emitted

• current through the photocell

• speed of the electrons

Light of frequency 2.0 × 10¹⁵ Hz is incident on a metal surface. The work function of the metal is 4.6 × 10^–19 J.

Which statement is correct?

• No photoelectrons are released.

• Photoelectrons are released with a maximum kinetic energy of 3.1 × 10^–19 J.

• Photoelectrons are released with a maximum kinetic energy of 8.7 × 10^–19 J.

• Photoelectrons are released with a maximum kinetic energy of 18 × 10^–19 J.

Photons of energy 1.0 × 10^–18 J are incident on a metal surface and cause the emission of electrons from the metal surface.

Which statement about the emitted electrons is correct?

• They each have a kinetic energy of 1.0 × 10^–18 J.

• They each have a kinetic energy that is a multiple of 1.0 × 10^–18 J.

• Their mean kinetic energy is 1.0 × 10^–18 J

• The kinetic energy of each must be less than 1.0 × 10^–18 J.

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?

• 
• 
• 
• 

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?

• 0.19 eV

• 4.3 eV

• 6.9 eV

• 8.4 eV

The graph shows how the maximum kinetic energy E_k of photoelectrons emitted from a metal surface varies with the reciprocal of the wavelength λ of the incident radiation.

What is the gradient of this graph?

• c

• h

• hc

• $\frac{h}{c}$

Which statement suggests that electrons have wave properties?

• Electrons are emitted in photoelectric effect experiments.

• Electrons are released when atoms are ionised.

• Electrons produce dark rings in diffraction experiments.

• Electron transitions in atoms produce line spectra.

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

• Increases - Unchanged

• Decreases - Increases

• Increases - Decreases

• Decreases - Unchanged

When comparing X-rays with UV radiation, which statement is correct?

• X-rays have a lower frequency.

• X-rays travel faster in a vacuum.

• X-rays do not show diffraction and interference effects.

• Using the same element, photoelectrons emitted using X-rays have the greater maximum kinetic energy.