Question

A clean metal surface is irradiated with light of three different wavelengths λ1, λ2, and λ3. The kinetic energies of the ejected electrons are as follows: λ1: 7.2 ´ 10-20 J; λ2: approximately zero; λ3: 5.8 ´ 10-19 J. Which light has the shortest wavelength and which has the longest wavelength? Determine the threshold frequency, νo, for this metal.

a. Calculate the wavelength and threshold frequency as specified.
b. Explain the photoelectric effect.
c. Ignore the given specifications.
d. Discuss the interference pattern of light.

Answer 1

The photoelectric effect is the phenomenon where electrons are ejected from a metal surface when it is exposed to light with a certain threshold frequency. From the given kinetic energies, we can determine the shortest and longest wavelengths of the light. Using the energy values, we can calculate the threshold frequency for the metal.

Step-by-step explanation:

The photoelectric effect is the phenomenon where electrons are ejected from a metal surface when it is exposed to light with a certain threshold frequency. In this case, the kinetic energies of the ejected electrons are given for three different wavelengths: λ1, λ2, and λ3. From this information, we can determine the shortest and longest wavelengths of the light.

The ejected electron with the highest kinetic energy corresponds to the shortest wavelength (λ1: 7.2 ´ 10-20 J) and the ejected electron with the lowest or zero kinetic energy corresponds to the longest wavelength (λ2: approximately zero).

To determine the threshold frequency, νo, we can use the equation E = hv, where E is the energy of the ejected electron, h is Planck's constant (6.63 × 10^-34 J·s), and v is the frequency of the incident light. By rearranging the equation, we can solve for the threshold frequency: νo = E/h. Using the energy values provided, we can calculate the corresponding frequencies and find the threshold frequency for the metal.