Question

Clara made a chart to summarize some of the evidence that supports the big bang theory. Which best describes Clara’s error? During redshift, the light source and observer move closer together, not farther apart. The CMB is blue-shifted, not red-shifted, to the microwave region. The temperature of the CMB is cooler, not hotter, than at the time of the big bang. The redshift indicates approaching, not receding, galaxies.

Answer 1

Redshift: a shift towards lower frequency. If the source moves towards the observer, the frequency will be observed as higher, and this is called blueshift.

The CMB is redshifted, not blueshifted, since it went from very high energy (frequency) to microwave frequency, which is very long wavelength and lower frequency.

It is true that the CMB is cooler now than it was before.

Redshift indicates receding galaxies, not approaching ones.

Answer 2

C. The temperature of the CMB is cooler, not hotter, than at the time of the big bang.

Hope this helps