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]
7 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A skydiver of mass 75 kg jumps from a plane.
Gravitational field strength = 9.8 N/kg.
.1
At one moment the air resistance on the skydiver is 285 N. Calculate the acceleration of the skydiver at this moment.
[3 marks]
.2
Explain why the skydiver reaches a terminal velocity.
[4 marks]
4 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
A box is dragged across a rough floor with a constant force of 150 N. 4500 J of work is done.
.1
Calculate the distance the box moves.
[2 marks]
.2
The bottom of the box and the floor get slightly warmer. Explain why.
[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.
[2 marks]
5 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
The graph shows how the distance travelled by a cyclist changes with time.
05101520253020406080100Time (s)Distance (m)
.1
Determine the speed of the cyclist during the first 10 s.
[2 marks]
.2
Describe the motion of the cyclist between 10 s and 20 s.
[1 mark]
.3
Calculate the average speed of the cyclist for the whole 30 s.
