Three identical rod are joined together to form a equilateral triangle as shown, lateral surfaces of rod are insulated. Temperature of end $A$ and $B$ are maintained at $100°\mathrm{C}$ and $200°\mathrm{C}$ respectively as shown in figure. If temperature at point $P$ which is mid point of rod $BC,$ is $T°\mathrm{C}$ then value of $\left(\frac{T}{25}\right)$ in ${}^{\circ }\mathrm{C}$ ?

When a copper ball is heated, the largest percentage increase will occur in its,

The portion $AB$ of the indicator diagram representing the state of matter denotes:

Five rods with same dimensions are arranged as shown in the figure. They have thermal conductivities, $K_1, K_2, K_3, K_4$ and $K_5$ when points $A$ and $B$ are maintained at different temperatures. No heat flows through the central rod $CD$ if:

Two spherical objects (I) and (II) are placed in same surrounding, their emissivity (e) and radius are shown in figure. If in some time interval, $100 \mathrm{J}$ of energy is absorbed by the object (I), then amount of energy absorbed) by object (II) in same time interval comes out to be $\left(100N\right)\mathrm{J},$ find $N.$

Consider a hollow cylinder of inner radius $a$ and outer radius $2a,$ lateral surface of cylinder is insulated and there is a temperature difference of $\Delta T$ between its ends, and $E_0=\frac{N\pi a^{2}k\Delta T}{L}$ is the rate of energy flow, then value of $N$ is ( k : Thermal conductivity of material)