Hospitals use X-rays to form images of the inside of the body. A CT scan uses X-rays from many directions. The table shows some typical radiation doses.
Typical radiation dose in millisieverts: one chest X-ray 0.02; one CT scan of the chest 7.0; background radiation in one year, UK average, 2.7.
Source of radiation
Typical dose in mSv
One chest X-ray
0.02
One CT scan of the chest
7.0
Background radiation in one year (UK average)
2.7
.1
Calculate how many chest X-rays give the same dose as one CT scan of the chest.
[2 marks]
.2
Calculate the dose from one CT scan of the chest as a percentage of the yearly background dose.
[2 marks]
.3
A patient has had a cough for several months. Evaluate the use of a CT scan of the chest to find the cause.
[3 marks]
.4
Give one harmful effect of ultraviolet radiation on the human body.
[1 mark]
5 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
The diagram shows the horizontal forces on a car.
car3000 N driving force1800 N air resistance400 N friction
.1
Calculate the resultant force on the car.
[2 marks]
.2
Describe the effect of this resultant force on the motion of the car.
[1 mark]
.3
Air resistance is a contact force. Gravity is a non-contact force. Explain the difference.
[2 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A tired driver is driving fast on a wet road at night.
Explain how each of these factors affects the stopping distance of the car.
[6 marks]
6 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A long, straight wire passes vertically through a horizontal card. The current in the wire flows upwards, out of the card towards you as you look down on it. Small plotting compasses are placed on the card around the wire.
.1
Seen from above, which way do the magnetic field lines go round the wire?
[1 mark]
.2
Describe the pattern of the magnetic field lines drawn on the card.
[2 marks]
.3
The current is reversed. Predict what happens to the compass needles.
[1 mark]
.4
The wire is then wound into a long coil (a solenoid). Describe the magnetic field of the solenoid.
[2 marks]
7 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
Waves travel across a pond. A floating leaf moves up and down 5 times in 2.0 s. The distance between neighbouring crests is 0.40 m.
.1
Calculate the frequency of the waves.
[1 mark]
.2
Calculate the speed of the waves.
[2 marks]
.3
Calculate the period of the waves.
[2 marks]
.4
The leaf moves up and down but does not travel across the pond with the waves.
Explain what this shows about the waves.
