Need help for this transformers question (1 Viewer)

[rcpleo]

This question comes from the Exam Choice 2010 Physics Paper. With what I learnt in class, I don't understand how is the answer C. Any help is greatly appreciated. Thanks in advance

 

[eshay lad 69]

thats funny because This question comes from the Exam Choice 2010 Physics Paper. With what I learnt in class, I don't understand how is the answer C. Any help is greatly appreciated. Thanks in advance
Screen shot 2012-03-12 at 9.34.55 PM.png

 

[Fizzy_Cyst]

use faraday/lenz

EMF = -n (delta_phi/delta_t)

EMF is basically represented as the gradient of the graph, multiplied by -1.

At beginning, grad is max and positive, hence emf will be max and negative

then at turning point grad is zero, hence emf will be zero, after half a turn, grad is max and negative, hence emf max and positive, it then instantaneously changes back to what it was at beginning.

 

[rcpleo]

Thank you very much. Correct me if I'm wrong, but by what you are saying, the voltage-time graph is essentially the same as the flux time graph?

 

[Fizzy_Cyst]

The induced EMF graph will be a mirror image of the change in flux vs time graph