Photoelectric Effect Practice 2
10 problems · instant feedback · full explanations
Light ejects electrons only if each photon has enough energy: hf ≥ Φ. Brightness changes the number of electrons, not their energy.
Q1.
Who explained the photoelectric effect using photons?
Multiple choice · Easy
Q2.
400 nm light hits sodium (Φ = 2.75 eV). What is the max electron kinetic energy? (hc = 1240 eV·nm. Answer in eV.)
Numerical answer (eV) · Medium
Q3.
No electrons are ejected below the threshold frequency. What will eject them?
Multiple choice · Easy
Q4.
Increasing the brightness of above-threshold light:
Multiple choice · Medium
Q5.
Zinc has work function 4.3 eV. What is its threshold frequency? (h = 4.136e-15 eV·s. Answer in Hz.)
Numerical answer (Hz) · Medium
Q6.
Electrons with max KE 0.35 eV: what stopping voltage halts them? (V)
Numerical answer (V) · Hard
Q7.
The work function is the minimum energy needed to eject an electron from a metal surface.
True / False · Easy
Q8.
In the photoelectric effect, there is a measurable time delay before electrons are emitted.
True / False · Medium
Q9.
How does max electron kinetic energy vary with light frequency?
Multiple choice · Hard
Q10.
620 nm light (2.0 eV photons) shines brightly on sodium (Φ = 2.75 eV). How many electrons are ejected?
Multiple choice · Hard