Question

Figure shows a conducting square loop placed parallel to the pole-faces of a ring magnet. The pole-faces have an area of 1 cm² each and the field between the poles is 0.10 T. The wires making the loop are all outside the magnetic field. If the magnet is removed in 1.0 s, what is the average emf induced in the loop?

Answer 1

It is given that the magnitude of the magnetic field is 0.10 T and it is perpendicular to the area of the loop.
Also,
Area of the loop, A = 1 cm² = 10⁻⁴ m
Time taken to remove the magnet completely, T = 2 s
Initial magnetic flux, ϕ = \[\overrightarrow{B} . \overrightarrow{A}\] = BA cos(0)  = 10⁻¹ × 10⁻⁴ × 1 = 10⁻⁵

Now, the induced emf in the magnetic field is given by

\[e =  - \frac{∆ \phi}{∆ t} = \frac{{10}^{- 5} - 0}{1} =  {10}^{- 5}  = 10  \mu V\]