Induced emf,e = -L\(\frac{di}{dt}\)

For 0 ≤ t ≤ \(\frac{T}{4}\),

i-t graph is a straight line with positive constant slop.

∴ \(\frac{di}{dt}\) = constant

e = -ve and constant, For 0 ≤ t ≤ \(\frac{T}{4}\)

For \(\frac{T}{4}\) ≤ t ≤ \(\frac{T}{2}\)

i is constant ∴ \(\frac{di}{dt}\) = 0

e = 0\(\frac{T}{4}\) ≤ t ≤ \(\frac{T}{2}\)

For \(\frac{T}{2}\)≤ t ≤ \(\frac{3T}{4}\)

i-t graph is a straight line with negative constant slope.

∴ \(\frac{di}{dt}\) = constant

e = +ve and constant For \(\frac{T}{2}\)≤ t ≤ \(\frac{3T}{4}\)

For\(\frac{3T}{4}\)≤ t ≤ T,

i is zero ∴ \(\frac{di}{dt}\) = 0

e = 0 For \(\frac{3T}{4}\)≤ t ≤ T

From this analysis, the variation of induced emf with time as shown in the figure below.