Question

The north pole of a magnet is brought down along the axis of a horizontal circular coil (figure). As a result, the flux through the coil changes from 0.35 weber to 0.85 weber in an interval of half a second. Find the average emf induced during this period. Is the induced current clockwise or anticlockwise as you look into the coil from the side of the magnet ?

Answer 1

Given:
Initial flux, ϕ₁ = 0.35 weber
Final flux ϕ₂ = 0.85 weber
∴ Δϕ = ϕ₂ − ϕ₁
= (0.85 − 0.35) weber
= 0.5 weber
Also,
Δt = 0.5 s
The magnitude of the induced emf is given by
$e=\frac{∆\mathrm{\varphi }}{∆t}=\frac{0.5}{0.5}=1\mathrm{V}$


The induced current is anti-clockwise when seen from the side of the magnet.