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10 (a) Figure 23 shows a model dynamo - Edexcel - GCSE Physics - Question 10 - 2023 - Paper 2
Question 10
10 (a) Figure 23 shows a model dynamo. The dynamo contains a coil of wire that can spin inside a permanent magnet. The dynamo produces a D.C output. A teacher conn... show full transcript
Worked Solution & Example Answer:10 (a) Figure 23 shows a model dynamo - Edexcel - GCSE Physics - Question 10 - 2023 - Paper 2
Step 1
Which row of the table shows how the rotation of the handle has changed between (a) and (b)?
Answer
The correct answer is C: slower than (b) and opposite to (b). This is because the voltmeter's reading indicated a reduced voltage when the handle rotation changed, confirming the slower rotation. Additionally, the opposite direction of the readings in (a) and (b) reflects the change in the handle's operational direction.
Step 2
Explain why it is more difficult to turn the dynamo when it is connected to a lamp.
Answer
When the dynamo is connected to a lamp, an electrical load is placed on it. This load requires a current to flow through the circuit, generating an opposing magnetic field in the dynamo's coil. As a result, additional force is needed to overcome this induced magnetic field, making it more difficult to turn the handle. The energy is being converted into electrical energy, which opposes the motion due to Lenz's law.
Step 3
Calculate the potential difference across the secondary coil.
Answer
To calculate the potential difference across the secondary coil (Vs), we can use the transformer equation:
Substituting the known values gives:
Rearranging the equation, we find:
Evaluating this yields:
Thus, the potential difference across the secondary coil is 5.2 V.