The Doppler effect
Grade 11 Science Worksheet
Circle the best answer, or write your answer on the line.
A 400 Hz train horn approaches at 20 m/s. With sound at 343.3 m/s in 20 °C air, what frequency does a listener ahead hear, to the nearest tenth, Ari?
A 1000 Hz toy buzzer on a cart approaches at 5 m/s. With sound at 343.3 m/s in 20 °C air, what frequency does a listener ahead hear, to the nearest tenth, Bo?
A 300 Hz train horn approaches at 30 m/s. With sound at 343.3 m/s in 20 °C air, what frequency does a listener ahead hear, to the nearest tenth, Esme?
Read this first
A 400 Hz train horn passing at different speeds, in 20 °C air (worked out with 343.3 m/s for sound)
Train speed (m/s) Heard approaching (Hz) Heard moving away (Hz) 10 412 388.7 20 424.7 378 30 438.3 367.9 Using the table, how does the train's speed change the shift, Jun?
- Faster trains make smaller shifts
- Speed makes no difference
- Faster trains make bigger shifts
Using the table, what does a listener hear as a 20 m/s train moves away, Kira?
- 378.0 Hz
- 400 Hz
- 424.7 Hz
Using the table, by about how many hertz does the pitch drop as a 10 m/s train passes, Luz?
- About 400 Hz
- About 23 Hz
- About 12 Hz
Light from a distant galaxy is shifted toward longer, redder wavelengths. What does that show, Milo?
- The galaxy is moving toward us
- The galaxy is moving away
- The galaxy is cooling down
A star is moving toward us. Which way is its light shifted, Noah?
- Toward blue, shorter wavelengths
- It isn't shifted, since light is so fast
- Toward red, longer wavelengths
A listener on a moving train passes a horn that stands still beside the track. How does the horn sound while approaching it, Ren?
- The same, since the horn isn't moving
- Lower than its own pitch
- Higher than its own pitch
A buzzer rides on a cart, and a listener rides beside it at the same speed. What shift does the listener hear, Zee?
- A higher pitch
- A lower pitch
- None