Question

Question
Which situations might cause two observers (A and B) to measure different frequencies for the same vibrating object? Select the two correct answers. (1 point)
Responses

Observer A and Observer B are both stationary and at the same distance from the object.
Observer A and Observer B are both stationary and at the same distance from the object.

Observer A and Observer B are stationary but at different distances from the vibrating object.
Observer A and Observer B are stationary but at different distances from the vibrating object.

Observer A and Observer B are moving at different speeds relative to each other.
Observer A and Observer B are moving at different speeds relative to each other.

Observer A is stationary and Observer B is moving.
Observer A is stationary and Observer B is moving.
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Answer 1

The two situations that might cause Observer A and Observer B to measure different frequencies for the same vibrating object are:

1. **Observer A and Observer B are stationary but at different distances from the vibrating object.** - While the frequency of the sound produced by the object itself doesn't change, the intensity and the Doppler effect (if they move) can affect what they perceive, potentially leading to differences in perceived frequencies due to distance effects.

2. **Observer A is stationary and Observer B is moving.** - The Doppler effect causes the frequency of sound to change depending on the relative motion of the source and the observer. If Observer B is moving towards or away from the vibrating object, the frequency measured by B will differ from that measured by A, who is stationary.

The first and fourth options are correct.

Answer 2

Why do scientists observe blueshift in certain stars?(1 point)
Responses

Stars with higher temperatures emit more light waves at the blue end of the spectrum.
Stars with higher temperatures emit more light waves at the blue end of the spectrum.

Light wave frequencies increase as an object moves toward the observer.
Light wave frequencies increase as an object moves toward the observer.

Light wave frequencies decrease as an object moves toward the observer.
Light wave frequencies decrease as an object moves toward the observer.

Stars with lower temperatures emit more light waves at the blue end of the spectrum.

Answer 3

The correct response is:

**Light wave frequencies increase as an object moves toward the observer.**

Blueshift occurs when a light source, such as a star, is moving toward an observer, causing the wavelengths of its emitted light to compress, resulting in an increase in frequency and a shift toward the blue end of the spectrum.