In the photoelectric effect, what happens to the kinetic energy of the emitted e
Practice Questions
Q1
In the photoelectric effect, what happens to the kinetic energy of the emitted electrons if the frequency of the incident light is increased?
It decreases
It remains constant
It increases
It becomes negative
Questions & Step-by-Step Solutions
In the photoelectric effect, what happens to the kinetic energy of the emitted electrons if the frequency of the 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 energy that depends on its frequency (how fast the light waves oscillate). The energy of a photon is given by the formula E = hf, where h is Planck's constant and f is the frequency of the light.
Step 4: When light hits the material, if the energy of the photons is greater than a certain threshold (called the work function, φ), electrons are emitted.
Step 5: The kinetic energy (KE) of the emitted electrons can be calculated using the formula KE = hf - φ.
Step 6: If the frequency (f) of the incident light increases, the energy (hf) of the photons also increases.
Step 7: Since φ (the work function) is a constant for a given material, an increase in hf means that KE (the kinetic energy of the emitted electrons) will also increase.
