The current I through an inductor varies with time as a symmetric triangle: it rises linearly from zero to a maximum at T/2 and falls linearly to zero at T. Which graph gives the induced voltage across the coil? [Image]
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Question

The current I through an inductor varies with time as a symmetric triangle: it rises linearly from zero to a maximum at T/2 and falls linearly to zero at T. Which graph gives the induced voltage across the coil? [Image]

Options

G1 Physics · Accepted Answer

Step 1: For an inductor, induced emf is ε = −L·dI/dt. Step 2: During the rising-current half, dI/dt is a positive constant; hence ε is a negative CONSTANT. Step 3: During the falling-current half, dI/dt is a negative constant of equal magnitude; hence ε is a positive CONSTANT. Step 4: Therefore the emf graph consists of two opposite-sign horizontal segments separated at T/2. Match the provided graphical options. Final answer: (D), refer to source diagram / graph.