Quantum A Level multiple choice test

What is the maximum kinetic energy of electrons emitted from cesium (Cs), when light of frequency 1 x10¹⁵ Hz falls upon the metal? (work function for Cs is 1.8 eV)

• 7.728x10^-19 J
• 4.83 eV
• 1.864x10^-19 J
• 2.34 eV

Do the photons of violet light or the photons of red light, falling on a metal surface with the same intensity,cause emission of more electrons?

•  red light
• violet light
• same 

Find the cut-off wavelength for the photoelectric effect in tungsten (work function for tungsten is 4.5 eV)

• 138 nm
• 414 nm
• 552 nm
• 276 nm

Light emitted from a laser has wavelength 350 nm.  Each pulse of light from the laser lasts for only 1.2 × 10^–13 s.  The power delivered in a pulse is 8.0 × 10⁴ W.  Calculate the number of photons in a single pulse.

• 1.7 x 10¹⁰
• 2.2 x 10¹¹
• 2.9 x 10⁶
• 6.7 x 10¹⁷

The photoelectric effect is when:

• Electrons collide inside a metal to release photons.
• One incident metal electron releases one photon.
• One incident photon releases one electron from a metal.
• Photons are absorbed in to metal ions releasing electrons.

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-4

The following observations are made about the photoelectric effect:
1.   No electrons are emitted below the threshold frequency.
2.   Above the threshold frequency the energy of electrons depends only on the frequency of the light.
3.   Increasing intensity increases the number of emitted electrons.
Which (if any) of these observations can be explained by a wave theory of light?

• All of them.
• 1 and 2 only.
• 3 only.
• None of them.

Which statement about the photoelectric effect is correct?

• Electrons are emitted instantaneously.
• Electrons are not emitted below a certain wavelength.
• You can change the energy of the electrons by changing the intensity.
• Electron energy is independent of frequency.

The graph shows maximum kinetic energy of emitted electrons against frequency of incident light for a number of different metals.
The threshold frequency is determined by:

• the x-intercept.
• the y-intercept.
• the gradient.
• the area under the graph.

Tags

NGSS.HS-PS4-3

The graph shows maximum kinetic energy of emitted electrons against frequency of incident light for a number of different metals.
The work function is determined by:

• the x-intercept.
• the y-intercept.
• the gradient.
• the area under the graph.

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