Question

A geyser heats water flowing at a rate of 2.0 kg per minute from 30°C to 70°C. If the geyser operates on a gas burner, the rate of combustion of fuel will be ______ g min^-1.

[Heat of combustion = 8 × 10³ Jg^-1 Specific heat of water = 4.2 Jg^-1°C^-1]

Options

• 40

• 41

• 42

• 44

Answer 1

A geyser heats water flowing at a rate of 2.0 kg per minute from 30°C to 70°C. If the geyser operates on a gas burner, the rate of combustion of fuel will be 42 g min^-1.

Explanation:

Heat absorbed by water per min = 2 × 4200 × 40 = 336000J

Now, 8 × 10³ J of heat is produced by 1 gm.

So, 336000 J of heat is produced by 1 gm.

= `1/(8 xx 10^3) xx 336000` gm

So, the rate of combustion = 42 gm/min.