A liquid in a beaker has temperature $\theta \left( t \right)$ at time $t$ and ${\theta _0}$ is temperature of surroundings, then according to Newton's law of cooling the correct graph between loge ${\log _e}(\theta - {\theta _0})$ and $t$ is
Gravitation force is required for
A body cools from $60\,^oC$ to $50\,^oC$ in $10\, minutes$. If the room temperature is $25\,^oC$ and assuming Newton's law of cooling to hold good, the temperature of the body at the end of the next $10\, minutes$ will be ....... $^oC$
Two identical square rods of metal are welded end to end as shown in figure $(a),\, 20$ $calories$ of heat flows through it in $4\,minutes$ . If the rods are welded as shown in figure $(b)$ , the same amount of heat will flow through the rods in ...... $\min$
A wall has two layers $A$ and $B$ , each made of a different material. Both the layers have the same thickness. The thermal conductivity of the material of $A$ is twice that of $B$ . Under thermal equilibrium, the temperature difference across the wall is $36\,^oC$. The temperature difference across the layer $A$ is ......... $^oC$
Six identical conducting rods are joined as shown in figure. Points $A$ and $D$ are maintained at temperatures $200\,^oC$ and $20\,^oC$, respectively. the temperature of junction $B$ will be......... $^oC$