The current I through a coil increases linearly during 0 to T/4, remains constant during T/4 to T/2, then decreases linearly to zero during T/2 to 3T/4. Which graph represents its induced emf as a function of time? [Image]
Options

Question

The current I through a coil increases linearly during 0 to T/4, remains constant during T/4 to T/2, then decreases linearly to zero during T/2 to 3T/4. Which graph represents its induced emf as a function of time? [Image]

Options

G1 Physics · Accepted Answer

Step 1: Induced emf is ε = −L(dI/dt), which is the negative slope of the current–time graph. Step 2: For increasing current from 0 to T/4, emf is constant and negative. Step 3: For constant current T/4 to T/2, emf is zero. Step 4: For decreasing current T/2 to 3T/4, emf is constant and positive; thereafter it is zero. Final answer: (D), refer to source diagram / graph.