QCEVault

Electromagnetism — Question 171

Original QCE Vault practice · 5 marks

Q171 · Practice questionComplex unfamiliar5 marks

QUESTION 171 (5 marks)

The graph gives the signed magnetic flux per turn of an 8080-turn stationary coil. Positive flux is out of the page. The graph is piecewise linear. Define positive EMF as driving conventional current counterclockwise when viewed on the page; this is the circulation associated with the outward normal.
Flux per turn in mWb versus time in ms: points (0,0), (20,3), (50,3), (70,-1) are joined by straight lines. Positive flux is out of the page.
a)
Determine the signed EMF during each interval: 0<t<20 ms0<t<20\,\mathrm{ms}, 20<t<50 ms20<t<50\,\mathrm{ms} and 50<t<70 ms50<t<70\,\mathrm{ms}.
[3 marks]
b)
If the coil is a closed conducting circuit, explain the induced current direction in the last interval.
[2 marks]
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