The Photoelectric Effect (7.1.5)

Question 1

• Shining light on a metal ejects electrons, increasing the current registered on an ammeter.

Answer 1

• Shining light on a metal ejects electrons, increasing the current registered on an ammeter.

Question 2

• Albert Einstein extended Planck’s quantum theory to explain the photoelectric effect.

Answer 2

• Albert Einstein extended Planck’s quantum theory to explain the photoelectric effect.

Question 3

In the photoelectric effect, shining light on a metal
ejects electrons, increasing the current registered
on an ammeter.
Increasing the intensity of the light causes more
electrons to be ejected, but does not change the
kinetic energy of the ejected electrons.
However, increasing the frequency of light causes
the electrons to be ejected with higher kinetic
energies.
Below the threshold frequency (ν0), no electrons
are ejected from the metal.
In 1905, Albert Einstein extended Planck’s quantum
theory to explain the photoelectric effect.
Einstein suggested that light was made up of
discrete packets of energy, now called photons.
The energy of a photon (Ephoton) is equal to Planck’s
constant (h) times the frequency of the photon (ν).
In the photoelectric effect, an electron is only
ejected if the photon has enough energy to
overcome the attraction between the electron and
the nucleus. If the photon has more energy than is
required, the leftover energy is converted to kinetic
energy.
The energy required to eject an electron from a
metal is equal to the energy of a photon of light at
the threshold frequency (ν0). This energy is the
work function (Φ) of the metal.
Einstein’s explanation of the photoelectric effect
meant that light could be thought of as being made
up of particles which are capable of moving
electrons. This helped to explain other light-driven
reactions, such as vision.

Answer 3

In the photoelectric effect, shining light on a metal
ejects electrons, increasing the current registered
on an ammeter.
Increasing the intensity of the light causes more
electrons to be ejected, but does not change the
kinetic energy of the ejected electrons.
However, increasing the frequency of light causes
the electrons to be ejected with higher kinetic
energies.
Below the threshold frequency (ν0), no electrons
are ejected from the metal.
In 1905, Albert Einstein extended Planck’s quantum
theory to explain the photoelectric effect.
Einstein suggested that light was made up of
discrete packets of energy, now called photons.
The energy of a photon (Ephoton) is equal to Planck’s
constant (h) times the frequency of the photon (ν).
In the photoelectric effect, an electron is only
ejected if the photon has enough energy to
overcome the attraction between the electron and
the nucleus. If the photon has more energy than is
required, the leftover energy is converted to kinetic
energy.
The energy required to eject an electron from a
metal is equal to the energy of a photon of light at
the threshold frequency (ν0). This energy is the
work function (Φ) of the metal.
Einstein’s explanation of the photoelectric effect
meant that light could be thought of as being made
up of particles which are capable of moving
electrons. This helped to explain other light-driven
reactions, such as vision.