Transformers - exam practice
Transformers
Question 1 of 6
This question is about a step-down transformer.
State the name of the parts labelled A, B and C.
State if this is a step up or a step down transformer.
Explain the operation of the transformer above.
A step up transformer has 12,000 turns on the secondary coil. The primary coil has 450 turns.
Calculate the input voltage to the primary coil if the output voltage is 600 V.
Give the name of a suitable metal for the core of the transformer.
Transformers are used to increase the voltage output of power stations before distribution via the National Grid.
Explain why electricity is transmitted at high voltages.
What is the purpose of a transformer?
What happens in a step-down transformer?
A transformer has 600 turns on the primary coil and an input voltage of 230 V. The output voltage is 575 V. Calculate the number of turns on the secondary coil.
Which of the following is not a use of a transformer.
This question is about electricity transmission via the National Grid.
Label the diagram below to show the step up and step down transformers used in the National Grid.
Explain why step-up transformers are used at the output of power stations.
The output voltage of a power station is 25,000 V. Electricity is transmitted via the National Grid at 400 kV. The step up transformer has 150,000 turns on the secondary coil.
Calculate the number of turns on the primary coil.
A student is investigating how the number of turns on the secondary coil affects the output voltage.
State two control variables for the student's investigation.
The student's data is below.
Plot a graph of number of secondary turns against output voltage.
Use the graph to estimate the output voltage if there were 60 turns on the secondary coil.
The student concluded that if she doubled the number of turns on the secondary coil, the output voltage would double.
Do you agree with the students conclusion? Explain why.
Draw a labelled diagram of a transformer.
Explain how a transformer works to increase the voltage of an alternating current input.
A transformer has 120 turns on the primary coil and an alternating input of 15 V.
Calculate the number of turns on the secondary required to increase the voltage to 90 V.