Answer:
Step-by-step explanation:
If L be inductance and i be current , flux associated with it
Φ = L i
emf induced = dΦ / dt = L di / dt
Putting the given values
emf induced = 3 V , L = 3 H
di = 8 - 3 = 5 A
dt = ?
3 = 3 x 5 / dt
dt or time duration = 3 x 5 / 3
= 5 sec .