A geyser heats water flowing at a rate of $2.0 kg$ per minute from $30^{\circ} C$ to $70^{\circ} C$. If geyser operates on a gas burner, the rate of combustion of fuel will be $\dots \; g \min ^{-1}$

[Heat of combustion $=8 \times 10^{3} Jg ^{-1}$  Specific heat of water $=4.2 Jg ^{-1} \; { }^{\circ} C ^{-1}$ ]

$100 \,gm$ of ice at $0°C$ is mixed with $100\, g$ of water at $100°C.$ What will be the final temperature of the mixture .......... $^oC$

$300 \,gm$ of water at $25^{\circ} C$ is added to $100 \,gm$ of ice at $0^{\circ} C$. The final temperature of the mixture is ........... $^{\circ} C$

A block of ice with mass $m$ falls into a lake. After impact, a mass of ice $m/5$ melts. Both the block of ice and the lake have a temperature of $^o C$. If $L$ represents the heat of fusion, the minimum distance the ice fell before striking the surface is

Calorimeters are made of which of the following

A drilling machine of $10\,KW$ power is used to drill a bore in a small aluminium block of mass $8\,kg.$ If $50\%$ of power is used up in heating the machine itself or lost to the surroundings then  ........ $^oC$  is the rise in temperature of the block in $2.5\,minutes$

[specific heat of aluminium $= 0.91\,J/g\,\,^oc$ ]