A gas based geyser heats water flowing at the rate of 5.0 litres per minute from 27°C to 87°C. The rate of consumption of the gas is 3em g/s. (Take heat of combustion of gas = 5.0 × 10⁴ J/g, specific heat capacity of water = 4200 J/kg·°C) (a) 4.2 (b) 2.1 (c) 0.21 (d) 0.42

Answer: (d). Mass flow = 5 kg/min = 1/12 kg/s. Heat per second = 1/12 × 4200 × 60 = 21000 J/s Gas rate = (21000)/(5 × 10⁴) = 0.42 g/s So the answer is (d) 0.42.

A gas based geyser heats water flowing at the rate of 5.0 litres per… | JEE Main 2026 (21 Jan, Shift 1)

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Calorimetry, Latent Heat & Mechanical Equivalent of Heat

A gas based geyser heats water flowing at the rate of 5.0 litres per minute from $27^{\circ}\text{C}$ to $87^{\circ}\text{C}$ . The rate of consumption of the gas is $\underline{\hspace{3em}}\text{ g/s}$ .

(Take heat of combustion of gas $= 5.0 \times 10^{4}\text{ J/g}$ , specific heat capacity of water $= 4200\text{ J/kg}\cdot{}^{\circ}\text{C}$ )

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Answer: (d)

Mass flow $= 5\text{ kg/min} = \tfrac{1}{12}\text{ kg/s}$ .
Heat per second $= \tfrac{1}{12} \times 4200 \times 60 = 21000\text{ J/s}$
Gas rate $= \dfrac{21000}{5 \times 10^4} = 0.42\text{ g/s}$
So the answer is (d) $0.42$ .

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