What phenomenon demonstrates light behaving as a particle?
The photoelectric effect.
What occurs during the photoelectric effect?
Electromagnetic radiation directed at a metal ejects electrons from its surface.
What type of light is typically used to demonstrate the photoelectric effect on zinc?
Ultraviolet light.
What device is often used to measure the photoelectric effect?
A digital coulomb meter or a gold leaf electroscope.
What is the formula for calculating the energy of a photon?
E = hf, where E is energy in joules, h is Planck’s constant, and f is frequency in hertz.
How is the energy of a photon related to its frequency?
The energy is directly proportional to the frequency and inversely proportional to the wavelength.
What is the threshold frequency?
The minimum frequency of a photon required to eject an electron from a metal surface.
What is the work function?
The minimum photon of energy required to release an electron from a metal surface.
What is the relationship between the work function and threshold frequency?
Work function (w0) = Planck’s constant (h) × threshold frequency (f0).
What happens if the frequency of light is below the threshold frequency?
No photoelectric current occurs; no electrons leave the surface of the metal.
What effect does increasing the frequency of light have on the kinetic energy of ejected electrons?
It increases the kinetic energy of the ejected electrons.
What happens to the number of ejected electrons if the intensity of light is increased?
The number of ejected electrons increases, but their kinetic energy remains the same.
What is the formula for the kinetic energy of an ejected electron?
Ek = hf - hf0, where Ek is kinetic energy, hf is energy of the photon, and hf0 is the work function.
What is the significance of a positively charged electroscope in the photoelectric effect?
The photoelectric effect will not occur if the electroscope is positively charged.
Why does white light not cause the photoelectric effect?
The photons in white light do not have sufficient energy to release electrons.
How do different metals affect the threshold frequency?
Different metals have different threshold frequencies based on how much energy their electrons require to escape.
What role does Planck’s constant play in the photoelectric effect?
Planck’s constant is used to calculate the energy of photons and the work function of metals.
What happens to the energy of photons as the frequency increases?
The energy of the photons increases.
