The coefficient of apparent expansion of a liquid when determined using two different vessels $A$ and $B$ are $\gamma_1$ and $\gamma_2$ respectively. If the coefficient of linear expansion of the vessel $A$ is $\alpha $, then coefficient of linear expansion of $B$

Explain why :

$(a)$ a body with large reflectivity is a poor emitter

$(b)$ a brass tumbler feels much colder than a wooden tray on a chilly day

$(c)$ an optical pyrometer (for measuring high temperatures) calibrated for an ideal black body radiation gives too low a value for the temperature of a red hot iron piece in the open, but gives a correct value for the temperature when the same piece is in the furnace

$(d)$ the earth without its atmosphere would be inhospitably cold

$(e)$ heating systems based on circulation of steam are more efficient in warming a building than those based on circulation of hot water

A bimetallic strip consists of metals $A$ and $B$ . It is mounted rigidly at the base as shown. The metal $A$ has a higher coefficient of expansion to that for metal $B$ . When bimetallic strip is placed in a cold bath it will

If there are no heat losses, the heat released by the condensation of $x$ gm of steam at $100^o C$ into water at $100^o C$ can be used to convert $y$ gm of ice at $0^o C$ into water at $100^o C$. Then the ratio $y : x$ is nearly

$1\, kg$ of ice at $-10\,^oC$ is mixed with $4.4\, kg$ of water at $30\,^oC$. The final temperature of mixture is   …….. $^oC$ (specific heat of ice is $2100\, J/kg/k$)