In the photoelectric effect, what happens to the kinetic energy of emitted elect
Practice Questions
Q1
In the photoelectric effect, what happens to the kinetic energy of emitted electrons if the frequency of incident light is increased?
It decreases
It remains constant
It increases linearly with frequency
It increases with the square of frequency
Questions & Step-by-Step Solutions
In the photoelectric effect, what happens to the kinetic energy of emitted electrons if the frequency of incident light is increased?
Correct Answer: Kinetic energy increases.
Step 1: Understand the photoelectric effect. This is when light hits a material and causes it to emit electrons.
Step 2: Know that light can be thought of as made up of particles called photons.
Step 3: Each photon has a certain amount of energy, which depends on its frequency. Higher frequency means more energy.
Step 4: The energy of a photon is given by the formula E = hf, where E is energy, h is Planck's constant, and f is frequency.
Step 5: When a photon hits an electron, it can give the electron enough energy to escape from the material.
Step 6: The kinetic energy (KE) of the emitted electron is calculated using the formula KE = hf - φ, where φ is the work function (the energy needed to release the electron).
Step 7: If the frequency (f) of the incident light increases, the energy (hf) of the photon increases.
Step 8: Since φ (the work function) is constant for a given material, an increase in hf means that KE will also increase.
Step 9: Therefore, the kinetic energy of the emitted electrons increases linearly with the frequency of the incident light.
