Question:easy

The current flowing through the inductor of self inductance 'L' is continuously increasing at constant rate. The variation of induced e.m.f. (e) versus \(\frac{dI}{dt}\) is shown graphically by figure

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Write e = -L dI/dt. It is a straight line through the origin with negative slope.
Updated On: Oct 1, 2026
  • A
  • B
  • C
  • D
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The Correct Option is C

Solution and Explanation

Step 1: Start from Faraday's law:
The flux linked with the coil is $\Phi = LI$. The induced e.m.f. is $e = -\frac{d\Phi}{dt} = -L\frac{dI}{dt}$ since $L$ is constant.

Step 2: Shape of the graph:
e is directly proportional to dI/dt, so the graph is a straight line through the origin. A curve is ruled out, and a horizontal line is ruled out because e changes when dI/dt changes.

Step 3: Sign:
Current is rising, so dI/dt is positive and e is negative. The line therefore lies in the negative e region, falling as dI/dt grows. This is figure C. Figure A rises, so its slope is $+L$, which is the wrong sign.

Final Answer:
Figure C is correct. \[ \boxed{\text{C}} \]
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