NEET Physics Thermal Properties Of Matter MCQs

The power radiated by a black body is ${\rm{p}}$ and it radiates maximum energy at wavelength ${\lambda _ \circ }$ If the temperature of the blackbody is now changes so that it radiates maximum energy at wavelength $\frac{3}{4}{\lambda _0}$, the power radiated by it becomes ${\rm{nP}}$.The value of ${\rm{n}}$ is

A copper rod of 88 cm and an aluminium rod of unknown length have their increase in length independent of increase in temperature. The length of aluminium rod is: $({\alpha _{Cu}}\, = \,1.7 imes \,{10^{ - 5}}\,{K^{ - 1}}\,{\rm{and}}\,{\alpha _{Al}}\, = \,2.2 imes \,{10^{ - 5}}\,{K^{ - 1}})$

The unit of thermal conductivity is:

Two identical bodies are made of a material for which the heat capacity increases with temperature. One of these is at ${100^{\rm{o}}}C$, while the other one is at ${{\rm{0}}^{\rm{o}}}C$, If the two bodies are brought into contact, then assuming no heat loss, the final common temperature is

A body cools from a temperature 3T to 2T in 10 minutes. The room temperature is $T$. Assume that Newton’s law of cooling is applicable. The temperature of the body at the end of next 10 minutes will be

A given sample of an ideal gas occupies a volume $V$ at a pressure $P$ and absolute temperature $T$. The mass of each molecule of the gas is $m$. Which of the following gives the density of the gas?

Coefficient of linear expansion of brass and steel rods are ${{\rm{\alpha }}_1}\,{\rm{and}}\,{{\rm{\alpha }}_2}$. Lengths of brass and steel rods are ${l_1}\,{\rm{and}}\,{l_2}$ respectively. If $({l_2}\,{\rm{ - }}\,{l_1})$ is maintained same at all temperatures, which one of the following relations holds good?

A spherical black body with a radius of $12\;{\rm{ cm}}$ radiates ${\rm{450\; Watt}}$ power at ${\rm{500\; K}}{\rm{.}}$If the radius were halved and the temperature doubled, the power radiated in watt would be