Trace sound-frequency changes to source motion, read stellar spectral shifts to infer direction, and use galaxy red-shift with Hubble’s law to estimate distance.
This question is about the Doppler effect.
Georgia carries out an experiment to measure the speed of mosquitoes. She sets up a microphone to record the sounds of passing mosquitoes.
One mosquito is moving in a straight line with constant speed and passes very close to the microphone as seen in the diagram. The mosquito produces a sound of constant frequency. The speed of sound in air is .
The maximum frequency recorded is 751 Hz and the minimum frequency recorded is 749 Hz . Explain this observation.
This question is about the Doppler effect.
The diagram shows wavefronts in air produced by a stationary source S of sound.
The distance between successive wavefronts is equal to the wavelength of the sound.
The speed of sound is c.
On the diagram, sketch three successive wavefronts produced when S is moving to the left at a speed of 0.5 c.
Star A is a main sequence star.
The data for Star A and the Sun are given in a table.
The peak wavelength of the radiation from Star A is measured by an observer on Earth. The observed wavelength is 0.007 % less than the peak wavelength emitted by Star A (about 560 nm).
Outline how this difference arises.
Determine the speed, in , of Star A relative to Earth.