Question

lesson 27 - properties of waves
which two have a directly proportional relationship?
□ energy
□ frequency
□ wavelength

Explanation:

Direct proportionality means as one quantity increases, the other increases by a constant factor. For waves, energy ($E$) and frequency ($f$) follow Planck's equation $E = hf$ (where $h$ is Planck's constant), so $E \propto f$. Wavelength ($\lambda$) and frequency are inversely proportional ($c = \lambda f$, so $\lambda \propto 1/f$).

Answer:

energy, frequency