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A teacher demonstrated the motor effect - AQA - GCSE Physics Combined Science - Question 4 - 2022 - Paper 2
Question 4
A teacher demonstrated the motor effect. Figure 5 shows the equipment used. Figure 5 Explain why there is a force on the wire when there is a current in the wire.... show full transcript
Worked Solution & Example Answer:A teacher demonstrated the motor effect - AQA - GCSE Physics Combined Science - Question 4 - 2022 - Paper 2
Step 1
Explain why there is a force on the wire when there is a current in the wire.
Answer
There is a force on the wire because of the interaction between the magnetic field generated by the current in the wire and the external magnetic field from the permanent magnets. The current creates its own magnetic field, which interacts with the magnetic field of the magnets, resulting in a net force acting on the wire.
Step 2
Explain how the direction of the force on the wire can be predicted.
Answer
The direction of the force can be predicted using Fleming's left-hand rule. According to this rule:
- Place the first finger of the left hand in the direction of the magnetic field (from north to south).
- Point the second finger in the direction of the current (from positive to negative).
- The thumb will point in the direction of the force acting on the wire.
Step 3
Explain one way that the motor could be changed to increase the rate at which the coil rotates.
Answer
One way to increase the rate at which the coil rotates is to increase the number of turns of wire on the coil. This would enhance the magnetic field interaction and increase the torque on the coil, leading to a faster rotation.