5 Photoelectric Effect and UV Catastrophe

What did Einstein propose to explain the photoelectric effect?

• Light behaves purely as a wave.

• Light is made of particles called photons.

• Electrons emit light when they are heated.

• The intensity of light is the key factor in ejecting electrons from metal.

What is the threshold frequency in the context of the photoelectric effect?

• The maximum frequency of light that can be absorbed by electrons.

• The frequency at which light begins to behave as a particle.

• The minimum frequency of incident light required to eject electrons from a metal surface.

• The frequency at which all electrons are ejected from the metal surface.

What does the work function represent in the photoelectric effect?

• The energy required to move an electron within the metal.

• The maximum kinetic energy of ejected electrons.

• The minimum energy needed to eject an electron from the metal surface.

• The total energy of all ejected electrons.

How did Max Planck contribute to the understanding of the photoelectric effect?

• By proposing that light could be absorbed or emitted in discrete quantities called quanta.

• By discovering the electron.

• By suggesting that light intensity is directly responsible for the photoelectric effect.

• By proving that light behaves only as a wave.

What problem does the term "ultraviolet catastrophe" refer to?

• The prediction that black bodies at low temperatures emit large amounts of ultraviolet light.

• The failure of classical mechanics to explain the stability of atoms.

• The observed decrease in energy emitted by a black body at ultraviolet frequencies.

• The theoretical prediction of infinite energy radiated by a black body at high frequencies.

How does the quantum nature of light solve the ultraviolet catastrophe problem?

• By limiting the energy that can be emitted at high frequencies.

• By increasing the intensity of light at all frequencies.

• By allowing infinite energy at ultraviolet frequencies.

• By treating light as a continuous wave.

Which equation correctly represents the relationship between the energy of a photon and its frequency?

What is the significance of Planck's constant in quantum mechanics?

• It determines the speed of light in a vacuum.

• It is the proportionality constant between the energy and frequency of a photon.

• It represents the maximum possible energy of a photon.

• It is the threshold frequency below which the photoelectric effect cannot occur.

Why does increasing the intensity of light below the threshold frequency not result in the ejection of electrons?

• Because the energy of individual photons is insufficient to overcome the work function.

• Because the electrons absorb too much energy and become trapped.

• Because the light behaves as a wave at low intensities.

• Because the metal surface reflects all the light.

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.