Question

Show that current leads the voltage in phase by pie/2 in an ac circuit through an inductor

Answer 1

Your que is wrong
Current is not lead in circuit contains inductor only but lagging by a phase of pi/2
In circuit containing capacitor only current leads by a phase of pi/2 from boltage

Answer 2

Hey !!

If                     V = V₀ sinωt

                     q = CV = CV₀sinωt

    ∴                 I = dq/dt = ωCV₀ cosωt

(or)               I = ωCV₀ sin(ωt + π/2)

So, the current leads the applied voltage in phase by π/2

Good luck !!