Specific heat capacity and latent heatEdexcel A-Level Physics: Mind map

Exam questions on Specific heat capacity and latent heat

1. A 2.0 kW electric kettle contains 1.5 kg of water at 20 °C. The water is heated to 100 °C and the kettle is then switched off. The specific heat capacity of water is 4180 J kg⁻¹ K⁻¹. In practice the kettle takes 280 s to do this.
   Calculate the energy transferred to the surroundings and the kettle itself while the water is being heated.2 marks
2. A student determines the specific latent heat of fusion of ice. A 60 W heater is placed in crushed ice at 0 °C in a funnel above a beaker. An identical funnel of ice without a heater is set up beside it. After 300 s the heated funnel has produced 62.0 g of melted water and the other funnel has produced 8.0 g.
   Calculate the specific latent heat of fusion of ice from these results.2 marks
3. A student calibrates an NTC thermistor so that it can be used as the sensor in a thermostat for a greenhouse heater. The thermistor is in series with a 4.0 kΩ fixed resistor across a 6.0 V supply, and the output p.d. is taken across the fixed resistor. A relay switches the heater off when the output p.d. rises to a set value.
   Describe how the student could calibrate the thermistor circuit.3 marks