A student says: "A stationary pair of magnets pushes apart, so momentum has been created. Two carts then collide and stick together, so momentum is destroyed." Both events occur on horizontal low-friction tracks.
Evaluate these two claims using momentum and energy, stating the system you consider.
[6 marks]
5 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
An imaging leaflet gives typical effective doses: one chest X-ray 0.020 mSv and one CT examination 4.0 mSv. These values are supplied; you do not need to recall dose units.
.1
Calculate the number of chest X-rays giving the same listed total dose as one CT examination.
[2 marks]
.2
Explain why the dose comparison alone cannot decide whether a patient should have the CT examination.
[3 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A worker is near a sealed radioactive source for a short time. Another worker has radioactive dust on a glove. A supervisor recommends tongs, shielding and careful removal of the contaminated glove.
Explain the different hazards and how the precautions reduce them.
[6 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A light pulse and a sound pulse leave the same device simultaneously. The observer is 680 m away. Take sound speed as 340 m/s and light speed as 3.0×108 m/s.
.1
Calculate the travel time of the sound.
[2 marks]
.2
Explain why timing from the visible flash to the sound is a reasonable way to measure the sound travel time here.
[2 marks]
5 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
In a specific heat capacity investigation, a 0.60 kg block receives 7200 J from a heater. Its temperature rises from 18 °C to 38 °C. A second run with the same block and input energy gives a rise of only 16 °C.
.1
Calculate the specific heat capacity using the first run.
[3 marks]
.2
The student claims that the second run proves the metal has changed. Evaluate the claim and describe one check on the temperature measurement.
