please explain this part in a simpler way - Physics - Heat and Energy

Question

please explain this part in a simpler way

Dhritabrata Nag · Accepted Answer

Dear Student,
<img alt="" src=
"https://s3mn%20mnimgs%20com/img/shared/content_ck_images/ck_6181367447485%20jpg"
style="width: 1023px; height: 526px;">Regards