A solenoid produces a field resembling that of a bar magnet. A compass near end X points away from X with its north-seeking end. The current is then reversed.
.1
Determine the initial polarity of X and its polarity after reversal. Explain the reasoning.
[2 marks]
.2
Compare the field inside a long solenoid with its field near an open end.
[2 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
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]
5 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
In a collision test the total momentum before impact is 0.500 kg m/s. Three repeats give total momentum after impact of 0.492, 0.501 and 0.495 kg m/s, all in the original direction.
.1
Calculate the mean total momentum after impact.
[2 marks]
.2
The uncertainty in the mean is estimated as 0.010 kg m/s. Evaluate whether these results contradict conservation of momentum.
[3 marks]
4 marksHigher
Spec and skills
Original practice question
Answer and supported method checks
A bus travels at 12 m/s. A cyclist ahead travels at 5.0 m/s in the same direction. Initially they are 140 m apart. Both speeds remain constant until they meet.
.1
Calculate how long the bus takes to reach the cyclist.
[2 marks]
.2
Calculate how far the bus travels before reaching the cyclist.
[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.
