Modern Physics Practice — Photoelectric Effect, Relativity and Radioactivity
10 problems · instant feedback · full explanations
Modern physics breaks classical intuition, so lean on the formulas and the experiments behind them. Each problem here connects to one landmark result — know the result, and the math follows.
Q1.
The energy of a single photon is directly proportional to which property of light?
Multiple choice · Easy
Q2.
How much energy is equivalent to 1 gram of mass? Use c = 2.99792458 × 10⁸ m/s. Give the answer in joules.
Numerical answer (J) · Easy
Q3.
A 100 g sample has a half-life of 10 minutes. How much remains after 30 minutes?
Numerical answer (g) · Medium
Q4.
Shining brighter light of the same color on a metal in the photoelectric effect causes what?
Multiple choice · Medium
Q5.
True or false: nothing can travel faster than light in a vacuum.
True / False · Easy
Q6.
According to special relativity, how does a moving clock appear to run compared to an identical stationary clock?
Multiple choice · Medium
Q7.
What is the energy of a single photon of frequency 5.0 × 10¹⁴ Hz? Use h = 6.62607015 × 10⁻³⁴ J·s.
Numerical answer (J) · Medium
Q8.
True or false: increasing the intensity of light increases the kinetic energy of ejected photoelectrons.
True / False · Medium
Q9.
What is the difference between nuclear fission and fusion?
Multiple choice · Hard
Q10.
A wooden artifact shows one-eighth the carbon-14 activity of living wood. How old is it? (Half-life of C-14 = 5730 years.)
Numerical answer (years) · Hard