6 exam-style questions with full mark schemes and model answers. Write your own answer and the AI examiner marks it against the mark scheme.
The total stopping distance of a car is made up of the thinking distance and the braking distance.
Explain what is meant by thinking distance and braking distance, and describe how each of them is affected by an increase in the car's speed and by one further named factor for each (for example, the driver's condition or the state of the road). (6 marks)
A car is travelling at a constant speed of 12 m/s. The driver sees a hazard and reacts with a reaction time of 0.70 s before starting to brake. Once the brakes are applied, the braking distance is 24 m.
(a) Calculate the thinking distance. Use distance=speed×time. Show your working and give the unit. (2 marks)
(b) Calculate the total stopping distance of the car. (2 marks)
A step-down transformer is used to reduce the potential difference of an alternating supply. The primary coil has 1000 turns and is connected to a 230 V supply. The secondary coil has 100 turns.
(a) Calculate the potential difference across the secondary coil. Use VsVp=NsNp. Show your working and give the unit. (2 marks)
(b) State whether this transformer is a step-up or a step-down transformer, and give a reason. (1 mark)
Electricity can be generated from renewable and non-renewable energy resources.
(a) State what is meant by a renewable energy resource, and give one example. (2 marks)
(b) Give one environmental advantage of generating electricity from wind rather than from burning coal. (1 mark)
In a UK three-pin plug, the live, neutral and earth wires each have a job to do.
State the potential difference of the live wire relative to earth, and state the job of the earth wire. (2 marks)
The National Grid uses transformers to change the potential difference at which electricity is transmitted through the power lines.
State why electricity is transmitted through the National Grid at a very high potential difference. (1 mark)