A force-extension graph is straight from the origin to force 5.0 N and extension 0.040 m. A student says the work done stretching the spring equals 5.0×0.040 J.
.1
Calculate the energy actually stored in the spring.
[2 marks]
.2
Explain the error in the student's reasoning.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Two identical bar magnets are placed with their north poles facing one another across a small gap. A field sensor is moved along the line between the poles.
.1
Explain why the field can be very weak at the midpoint even though each magnet separately has a strong field there.
[2 marks]
.2
Explain the force between the magnets and how the result differs if one magnet is reversed.
[2 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A 12 V battery is connected to two identical fixed resistors in series. A voltmeter across one reads 6.0 V. The resistors are then connected in parallel across the same ideal battery; their resistances do not change.
Compare the voltage across each resistor, the current in each resistor and the total battery current in the two arrangements.
[4 marks]
5 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A rock has mass 0.54 kg and volume 200 cm³. A pupil writes its density as 0.0027 kg/m³.
.1
Calculate the correct density in kg/m³.
[3 marks]
.2
Explain why the pupil's numerical division is not sufficient to justify the stated unit.
[2 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Three wires in a mains flex are brown, blue and green-and-yellow. A voltmeter connected by a qualified technician reads about 230 V between brown and blue and about 0 V between blue and Earth.
Explain the role of each wire and why brown-to-Earth contact can cause an electric shock.
