7 marksFoundation and Higher
A current of 0.25 A flows through a 47 Ω resistor.
.1Calculate the power transferred in the resistor.
Give your answer to 2 significant figures.
[3 marks] .2The p.d. across the resistor is 11.75 V. In one minute, 15 C of charge flows through it.
Calculate the energy transferred in one minute.
[2 marks] .3Show that your answers to parts 1 and 2 agree, and explain why.
[2 marks] 5 marksFoundation and Higher
A student wants to find the density of a small irregular stone. They have a balance, a measuring cylinder and water.
.1Describe how the student can find the volume of the stone.
[2 marks] .2The water level rises from 50 cm³ to 70 cm³. The mass of the stone is 52 g.
Calculate the density of the stone.
[2 marks] .3Suggest one reason the student's value for the volume might be inaccurate.
[1 mark] 6 marksFoundation and Higher
A student measures the resistance of a length of wire. The diagram shows the correct circuit.
.1How is the voltmeter connected to the wire R?
[1 mark] .2The voltmeter reads 3.0 V. The ammeter reads 150 mA.
Calculate the resistance of the wire.
[3 marks] .3The student switches the circuit off between readings. Suggest why.
[2 marks] 4 marksFoundation
An electric kettle has an input power of 2000 W. The useful power output, heating the water, is 1800 W.
.1Calculate the efficiency of the kettle.
[2 marks] .2Calculate the power wasted by the kettle.
[1 mark] .3Give one way energy is wasted by the kettle.
[1 mark] 5 marksFoundation and Higher
A block of ice is heated at a steady rate. The graph shows how its temperature changes.
0481216202428324080120Time (min)Temperature (°C)ABCD
.1In which section of the graph is the water boiling?
[1 mark] .2Explain why the temperature does not change in section B, even though energy is still being transferred to the ice.
[2 marks] .3The mass of the ice is 0.50 kg. The specific latent heat of fusion of ice is 334 000 J/kg.
Calculate the energy needed to melt all of the ice.
[2 marks] 