Question

Due to the Doppler effect, a warm blackbody moving towards an observer at high velocity will appear.

A) Warmer than if it were not moving.
B) Colder than if it were not moving.
C) At the same temperature as if it were not moving.
D) To have more spectral lines than if it were not moving.
E) To have fewer spectral lines than if it were not moving.

Answer 1

The correct answer is B) Colder than if it were not moving. The Doppler effect causes the wavelengths of light emitted by a warm blackbody moving towards an observer to shorten, resulting in a shift towards bluer color and a perception of colder temperature.

Step-by-step explanation:

The correct answer is B) Colder than if it were not moving.

The Doppler effect is the shift of the wavelength of light due to the relative motion between the source of the light and the observer. When a warm blackbody is moving towards an observer at high velocity, the wavelengths of the light it emits appear shorter. This shift towards shorter wavelengths corresponds to a bluer color, which is perceived as a colder temperature. Therefore, the blackbody will appear colder than if it were not moving.