Radium-226 decays by emitting an alpha particle:
88226Ra→ZARn+24He
.1
Determine the mass number A of the radon nucleus.
[1 mark]
.2
Determine the atomic number Z of the radon nucleus.
[1 mark]
.3
Strontium-90 decays by beta emission. Describe what happens in the nucleus during beta decay.
[2 marks]
8 marksFoundation and Higher
Spec and skills
Original practice question
Answer and supported method checks
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
Spec and skills
Original practice question
Answer and supported method checks
An electric kettle has an input power of 2000 W. The useful power output, heating the water, is 1800 W.
.1
Calculate the efficiency of the kettle.
[2 marks]
.2
Calculate the power wasted by the kettle.
[1 mark]
.3
Give one way energy is wasted by the kettle.
[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.
