| Date | November 2011 | Marks available | 1 | Reference code | 11N.1.HL.TZ0.25 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 0 |
| Command term | Question number | 25 | Adapted from | N/A |
Question
The diagram shows the view from above as an airplane flies horizontally through the Earth’s magnetic field. The airplane is made of conducting material.
The direction of the induced emf will be from
A. P to R.
B. R to P.
C. S to Q.
D. Q to S.
Markscheme
B
Examiners report
There were, questionably, two plausible responses to this question – A and B. Both were accepted.
As the metallic wing moves through the Earth‟s magnetic field so an emf will be induced between R and P in such a direction as to move (positive) charge from R to P. This would indicate that B was the correct response.
But as a result of P being now more positive than R, it can be argued that an electric field is established from P to R. This would result in response A.
It is impossible to tell whether the confusion was due to the slightly ambiguous nature of the question or whether candidates were unable to use the correct hand to analyse the situation. But the poor showing in Q 23 would suggest it may be the latter; in which case this is an area of the syllabus that needs more attention.
