Physics

Problem

An electric kettle has a heating element of resistance

44\,\Omega

and is connected to a

220\,\text{V}

supply. The kettle contains

1\,\text{kg}

of water at

20^{\circ}\text{C}

. a. (i) Assuming that all electrical energy supplied is absorbed by the water, calculate the time required for the water to reach its boiling point,

100^{\circ}\text{C}

. (Specific heat capacity of water

= 4.2 \times 10^{3}\,\text{J}\,\text{kg}^{-1}\,^{\circ}\text{C}^{-1}

.) b. (ii) In practice some heat is lost to the surroundings. State two factors that could increase the time actually taken compared with the value calculated in part (i).

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