Two conducting cylinders of equal length but different radii are connected in series between two heat baths kept at temperatures $T _1=300 K$ and $T _2=100 K$, as shown in the figure. The radius of the bigger cylinder is twice that of the smaller one and the thermal conductivities of the materials of the smaller and the larger cylinders are $K _1$ and $K _2$ respectively. If the temperature at the junction of the two cylinders in the steady state is $200 K$, then $K _1 / K _2=$ . . . . .
$5$
$7$
$4$
$8$
The coefficient of linear expansion depends on
An iron tyre is to be fitted on to a wooden wheel 1m in diameter. The diameter of tyre is $6\, mm$ smaller than that of wheel. The tyre should be heated so that its temperature increases by a minimum of ........ $^oC$ (the coefficient of cubical expansion of iron is ${3.6 \times 10^{-5} } °C^{-1}$)
The coefficients of thermal expansion of steel and a metal $X$ are respectively $12 × 10^{-6}$ and $2 × 10^{-6} per^o C$. At $40^o C$, the side of a cube of metal $X$ was measured using a steel vernier callipers. The reading was $100 \,\,mm$.Assuming that the calibration of the vernier was done at $0^o C$, then the actual length of the side of the cube at $0^o C$ will be
The volume of a gas at $20°C$ is $100 \,cm^3$ at normal pressure. If it is heated to $100°C$, its volume becomes $125\, cm^3$ at the same pressure, then volume coefficient of the gas at normal pressure is
At $NTP$ water boils at $100°C.$ Deep down the mine, water will boil at a temperature