Density of air____________ with height.

Q. Assertion :A balloon filled with hydrogen stops rising after it has attained a certain height in the sky. Reason: As height increases, density of air decreases resulting in increase of buoyant force.

Q. A man grows into a giant such that his linear dimensions increases by a factor of $9$. If his density remains same, then stress on the leg will increase by a factor of
(Assume cubical shape of man with $L$ as edge length).

Q. Assertion :On a rainy day sound travel faster than on a dry day. Reason: When moisture is present in air the density of air increases.

Q. With rise in the temperature, resistance of carbon

Q. Assertion :A capillary is dipped in a liquid and liquid rises to a height $h$ in it. As temperature of the liquid is raised, the height $h$ increase (if the density of the liquid and angle of contact remain the same) Reason: Surface tension of a liquid decreases with the rise in its temperature.