ELECTROMAGNETIC INDUCTION
3 marks · NormalA student investigates how the induced voltage in a coil changes with the speed of a moving magnet. Her results are shown in the table.
| Speed of magnet (cm/s) | Induced voltage (V) |
|---|---|
| 2 | 0.6 |
| 4 | 1.2 |
| 6 | 1.8 |
| 8 | 2.4 |
Describe the relationship between speed and induced voltage shown by the data.
Predict the induced voltage if the speed of the magnet is increased to 10 cm/s.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) The induced voltage is directly proportional to the speed of the magnet.
(b) 3.0 V
Common mistakes: Failing to read correct pattern from table; Not applying proportionality correctly
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correctly states proportional relationship
M1 (b) · 1 mark · Uses proportionality to set up calculation
A1 (b) · 1 mark · Correctly calculates 3.0 V
Worked solution
a) The data show that induced voltage is directly proportional to speed (if speed doubles, voltage doubles, etc.).
b) Ratio V = (Induced voltage) / (Speed) = 0.6 / 2 = 0.3 V per cm/s.