IB Physics Topic 12

A beam of monochromatic radiation is made up of photons each of momentum p. The intensity of the beam is doubled without changing frequency. What is the momentum of each photon after the change?

• p/2

• p

• 2p

• 4p

Three observations of the behaviour of electrons are

I. electron emission as a result of the photoelectric effect

II. electron diffraction as an electron interacts with an atom

III. emission of radio waves as a result of electrons oscillating in a conductor.

Which observations are evidence that the electron behaves as a particle?

• I and II only

• I and III only

• II and III only

• I, II and III

A particle is confined within a nucleus. What is the order of magnitude of the uncertainty in the momentum of the particle?

• 10^–10 N s

• 10^–15 N s

• 10^–20 N s

• 10^–25 N s

When green light is incident on a clean zinc plate no photoelectrons are emitted. What change may cause the emission of photoelectrons?

• Using a metal plate with larger work function

• Changing the angle of incidence of the green light on the zinc plate

• Using shorter wavelength radiation

• Increasing the intensity of the green light

Monochromatic electromagnetic radiation is incident on a metal surface. The kinetic energy of the electrons released from the metal

• is constant because the photons have a constant energy.

• is constant because the metal has a constant work function

• varies because the electrons are not equally bound to the metal lattice.

• varies because the work function of the metal is different for different electrons.

Different metal surfaces are investigated in an experiment on the photoelectric effect. A graph of the variation of the maximum kinetic energy of photoelectrons with the frequency of the incident light is drawn for each metal. Which statement is correct?

• All graphs have the same intercept on the frequency axis.

• The work function is the same for all surfaces.

• All graphs have the same slope.

• The threshold frequency is the same for all surfaces.

A monochromatic light beam with a quantum energy of 9.0 eV is incident upon a photocell. The work function of the photocell is 4.1 eV. What is the maximum kinetic energy of the electron.

• 4.2 eV

• 4.4 eV

• 4.7 eV

• 4.9 eV

Tags

NGSS.HS-PS4-1

NGSS.HS-PS4-3

In an experiment, photoelectric effect is observed in metal A when light with frequency (f ) falls on the metal. If the light frequency used in this experiment is doubled, the photoelectrons

• Will not be ejected

• Will be ejected as observed in the previous

• Will be ejected with greater number of photoelectrons

• Will be ejected with greater kinetic energy

Tags

NGSS.HS-PS4-3

A metal surface is struck with light of λ = 400 nm, releasing a stream of electrons. If the light intensity is increased (without changing λ ), what is the result?

• More electrons are emitted in a given time interval

• Fewer electrons are emitted in a given time interval

• Emitted electrons are more energetic

• Emitted electrons are less energetic

Tags

NGSS.HS-PS4-3

The photoelectric effect only occurs if the light shining on the metal is:

• coherent.
• above a minimum intensity.
• above a minimum frequency.
• above a minimum wavelength.

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-4