Topic Menu

Cyber-chess a chess instruction site

Questions on Electric Circuits

Q7.The diagram shows a circuit for controlling an electric motor. This circuit can make the motor turn forwards or backwards.

Complete the table to show which lamp, if any, is lit and in which direction, if any, the motor turns.

Switch A
Switch B
Which lamp, if any, is lit?
Motor direction (forwards or backwards)
up
down
Lamp 1
forwards
up
up
None lit
Not moving
down
up
Lamp 2
backwards
down
down
None lit
Not moving

1 mark for each correct row

I have redrawn the circuits for you with the switches in each position to show you that the table is correct. A thick red line marks out the complete circuit in each case.

This is the sample one. It shows you which way the current has to be flowing for the motor to move 'forward'.

No battery in the circuit - so no current will flow.

No current here either - no battery in the circuit.

The current flows the opposite way now - so the motor will be in reverse.

 

3 marks