Question

1. what happens to the wavelength if the frequency increases (and speed stays the same)?

a) wavelength increases
b) wavelength stays the same
c) wavelength decreases
d) amplitude increases

1. light waves travel ____________ than sound waves in air.

a) slower
b) faster
c) the same speed
d) not at all

Explanation:

Question 1

The formula relating wave speed ($v$), frequency ($f$), and wavelength ($\lambda$) is $v = f\lambda$. If speed ($v$) is constant and frequency ($f$) increases, rearranging the formula to $\lambda=\frac{v}{f}$ shows that wavelength ($\lambda$) must decrease (since $v$ is fixed, a larger $f$ leads to a smaller $\lambda$). Option d is incorrect as amplitude is unrelated to this relationship.

In air, the speed of light is approximately $3\times10^{8}\, \text{m/s}$, while the speed of sound in air is about $343\, \text{m/s}$. So light waves travel much faster than sound waves in air.

Answer:

c) Wavelength decreases

Question 2