Question

How has the Doppler effect and the redshift of stars and galaxies indicated that the universe is expanding?

Answer 1

B is the answer because wavelengths from far away are red-shifted and short ones are blue-shifted

Answer 2

Answer:

Option C

Explanation:

As per the doppler's effect, when an object in the universe move at a fast speed away from the observer, its possesses a high wavelength as compared to its original wavelength.

Since red light has the highest wavelength, any object's wavelength moving towards a high values is said to be red shifted.

Thus, the higher the wavelength, the lower will be the frequency of an object and hence it moves at a faster speed away from the observer and hence the universe is said to be expanding.

Thus, option C is correct.