Spheres $P$ and $Q$ are uniformly constructed from the same material which is a good conductor of heat and the radius of $Q$ is thrice the radius of $P$. The rate of fall of temperature of $P$ is $x$ times that of $Q$. When both are at the same surface temperature, the value of $x$ is :

Two spheres of equal masses , one made up of lead and the other of copper have identical surface finish. If these two are heated upto the same temperature $\theta$ and allowed to cool in the surrounding temperature ${\theta }_0$, then the total amount of heat loss during the same time will be