A kettle containing of water at is heated by a coil heater of power

PHYSICS · Single correct · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter

Problem

A kettle containing

2\,\mathrm{L}

of water at

27\,^\circ\mathrm{C}

is heated by a coil heater of power

1\,\mathrm{kW}

. With its lid open, heat is lost to the atmosphere at a constant rate of

160\,\mathrm{J/s}

. In how much time will the water be heated to

77\,^\circ\mathrm{C}

? Take the specific heat capacity of water as

4.2\,\mathrm{kJ\,kg^{-1}\,^\circ C^{-1}}

. (1)

8\,\mathrm{min}\ 20\,\mathrm{s}

(2)

6\,\mathrm{min}\ 2\,\mathrm{s}

(3)

14\,\mathrm{min}

(4)

7\,\mathrm{min}