HW – Beats and Doppler Effect
1. Explain how wave interference produces beats.
2. You have three tuning forks – 260 Hz, 262 Hz, and 266 Hz. What beat frequencies can you
produce?
3. A piano tuner rings a tuning fork and plays a note on the piano at the same time. The piano
tuner hears 2 beats per second. She tightens the piano wire and then tests with the tuning fork
again. Now the piano tuner hears 1 beat per second. Should she tighten or loosen the piano
wire? EXPLAIN
4. You ring a 440 Hz tuning fork and an unknown tuning fork. You hear 5 beat/sec. What is the
frequency of the other tuning fork?
5. Astronomers studying the sun notice that light coming from one edge of the sun is of a higher
frequency than light coming from the opposite edge. What does this tell astronomers about the
sun?
6. A plane is flying at 300 m/s. Why is it impossible for it to make a sonic boom? Explain, using
your understanding of waves.