A CRO trace shows that 4 complete sound waves take to pass the reference line

PHYSICS · Single correct · A Level · Physics · Waves · Waves

Problem

A CRO trace shows that 4 complete sound waves take

8\,\text{ms}

to pass the reference line. What is the frequency of the sound? (a)

625\,\text{Hz}

(b)

250\,\text{Hz}

(c)

500\,\text{Hz}

(d)

2000\,\text{Hz}