3 (a) The resistance of a thermistor at 0 °C is 3840 Ω. At 100 °C the resistance is 190 Ω. When the thermistor is placed in water at a particular constant temperature, its resistance
is 2300 Ω.
(i) Assuming that the resistance of the thermistor varies linearly with temperature,
calculate the temperature of the water.
temperature = °C [2]
(ii) The temperature of the water, as measured on the thermodynamic scale of
temperature, is 286 K.
By reference to what is meant by the thermodynamic scale of temperature, comment
on your answer in (i).



[3]
(b) A polystyrene cup contains a mass of 95 g of water at 28 °C.
A cube of ice of mass 12 g is put into the water. Initially, the ice is at 0 °C. The water, of
specific heat capacity 4.2 × 103 J kg–1 K–1, is stirred until all the ice melts.
Assuming that the cup has negligible mass and that there is no heat exchange with the
atmosphere, calculate the final temperature of the water.
The specific latent heat of fusion of ice is 3.3 × 105 J kg–1.
temperature = °C [4]