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Question
The north pole of a magnet is brought down along the axis of a horizontal circular coil (see the following 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 ?
Solution
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
\[e = \frac{∆ \phi}{∆ t} = \frac{0 . 5}{0 . 5} = 1 V\]
The induced current is anti-clockwise when seen from the side of the magnet.
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