A 10 kW drilling machine is used to drill a bore in a small aluminium block of mass 8.0 kg. How much is the rise in temperature of the block in 2.5 minutes?
(Assuming 50% of power is used up in heating the machine itself or lost to the surroundings? Specific heat of aluminium $=0.91 J g^{-1} K^{-1}$.)
1. 103°C
2. 109°C
3. 211°C
4. 197°C

A copper block of mass 2.5 kg is heated in a furnace to a temperature of 500 °C and then placed on a large ice block. What is the maximum amount of ice that can melt?

(Specific heat of copper = $0.39 J g^{-1} K^{-1},$ the heat of fusion of water = 335 J/g)

1. 1.32 kg
2. 1.12 kg
3. 1.45 kg
4. 1.53 kg

In an experiment on the specific heat of a metal, a 0.20 kg block of the metal at \(150^{\circ}\mathrm{C}\) is dropped in a copper calorimeter (of water equivalent of 0.025 kg) containing 150 \(c m^{3}\) of water at \(27^{\circ}\mathrm{C}\). The final temperature is \(40^{\circ}\mathrm{C}\). The specific heat of the metal will be: (Heat   losses   to   the   surroundings   are   negligible)
1. \(0 . 40  ~ \text{Jg}^{- 1} \text{K}^{- 1}\)
2. \(0 . 43  ~ \text{Jg}^{- 1} \text{K}^{- 1}\)
3. \(0 . 54 ~ \text{Jg}^{- 1} \text{K}^{- 1}\)
4. \(0 . 61 ~ \text{Jg}^{- 1} \text{K}^{- 1}\)

A child of mass 30 kg running at a temperature of 101°F is given an antipyrin (i.e. medicine that lowers fever) which causes an increase in the rate of evaporation of sweat from his body. If the fever is brought down to 98 °F in 20 min, what is the average rate of extra evaporation caused, by the drug?

[Assume the evaporation mechanism to be the only way by which heat is lost. The mass of the child is 30 kg. The specific heat of the human body is approximately the same as that of water, and the latent heat of evaporation of water at that temperature is about 580 cal $g^{-1}$.]

1. 5.81 g/min
2. 4.39 g/min
3. 8.90 g/min
4. 3.05 g/min

A geyser heats water flowing at the rate of 3.0 liters per minute from 27 °C to 77 °C. If the geyser operates on a gas burner, what is the fuel consumption rate if its heat of combustion is $4.0\times {10}^4 J/g$?

1. 15.7 g per min
2. 15.10 g per min
3. 14.39 g per min
4. 17.11 g per min