3 mins read

2 mins read

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 identical masses of $5kg$ each fall on a wheel from a height of $10m$. The wheel disturbs a mass of $2kg$ water, the rise in temperature of water will be: