Questions

In troposphere and mesosphere, temperature declines with increasing altitude. In stratosphere and thermosphere, temperature increases with increasing altitude.The coldest temperatures in Earth’s atmosphere occur at the top of mesosphere, the Mesopause, especially in the summer near the pole.Transitional layers of atmosphere include tropopause, stratopause, and mesopause. These layers are relatively thin and are located between major layers of atmosphere. These have contrasting thermal properties. Hence, in these layers there is no change in temperature with change in altitude.

Heat lost by hot object = Heat gained by cold object

where we ignore heat gained or lost from/to the surroundings.

The study of heat gained and lost in this manner is often called Calorimetry.

Nuclear sizes are expressed in a unit called "Fermi" which is a unit of length equal to 10⁻¹⁵ metre (one femtometre), used in nuclear physics. It is similar to the diameter of a proton.