Physics · Oct / Nov 2021 · Paper 11 · Question 25

A student stands a distance x in front of a large wall. He claps his hands at a regular rate so that each clap coincides with the echo from the previous clap. In a time t, he claps his hands N times. Which expression is used to calculate the speed of sound in air?

1. A\frac{x}{Nt}
2. B\frac{2x}{Nt}
3. C\frac{Nx}{t}
4. D\frac{2Nx}{t}

As printed in the paper