A brass boiler has a base area of \(0.15~\text m^2\) and a thickness of \(1.0 ~\text{cm}.\) It boils water at a rate of \(6.0 ~\text{kg/min}\) when placed on a gas stove. What is the temperature of the part of the flame in contact with the boiler?
(Thermal conductivity of brass \(=109~\text{J s}^{-1}\text{m}^{-1}\text{K}^{-1},\) the heat of vaporization of water \(=2256\times 10^3~\text{J/kg}.\))
1. \(237.98^\circ\text C\)
2. \(150^\circ\text C\)
3. \(137.98^\circ\text C\)
4. \(100^\circ\text C\)

A ‘thermacole’ icebox is a cheap and efficient method for storing small quantities of

cooked food in summer in particular. A cubical icebox of side 30 cm has a thickness of

5.0 cm. If 4.0 kg of ice is put in the box, what is the amount of ice remaining after 6 h?

The outside temperature is 45 °C, and the coefficient of thermal conductivity of thermacole is $0.01 J s^{-1} m^{-1} K^{-1}.$$\left[Heat of fusion of water=335\times {10}^3 J k{g}^{-1}\right]$

1. 2.9 kg
2. 3.1 kg
3. 3.7 kg
4 4.10 kg

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 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

In an experiment on the specific heat of a metal, a \(0.20~\text{kg}\) block of the metal at \(150^{\circ}\text{C}\) is dropped in a copper calorimeter (of water equivalent of \(0.025~\text{kg}\)) containing \(150~\text{cm}^{3}\) of water at \(27^{\circ}\text{C}.\) The final temperature is \(40^{\circ}\text{C}.\) The specific heat of the metal will be: 
(the 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 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

Temperature is a measure of:

1. Hotness or coldness

2. Heat possessed by a body

3. Potential energy

4. Thermal energy

If in the winter season, the surface temperature of the lake is $1°\mathrm{C}$, the temperature at the bottom of the lake will be:

1. $1°\mathrm{C}$

2. $0°\mathrm{C}$

3. $4°\mathrm{C}$

4. All values less than $1°\mathrm{C}$ are possible.

The readings of a bath on Celsius and Fahrenheit thermometers are in the ratio of 2: 5. The temperature of the bath is:

1. $-26.66°\mathrm{C}$

2. $40°\mathrm{C}$

3. $45.71°\mathrm{C}$

4. $26.66°\mathrm{C}$

A hole is drilled in a copper sheet. The diameter of the hole is 4.24 cm at $27.0°\mathrm{C}$. The diameter of the hole, when it is heated to 35.0 °C, is:

1. less than 4.24 cm.

2. equal to 4.24 cm.

3. more than 4.24 cm.

4. Data insufficient