Electricity and Magnetism - SS2 Physics Past Questions and Answers - page 5

The induced EMF can be calculated using the formula: EMF = -N x (ΔΦ/Δt), where N is the number of turns and ΔΦ/Δt is the rate of change of magnetic flux.

   Given: N = 100 turns, ΔΦ/Δt = 0.2 T/s, A = 0.05 m²

   Substituting the values into the formula:

   EMF = -100 x (0.2 T/s) = -20 V

The magnitude of the induced EMF in the coil is 20 V.

The average induced EMF can be calculated using the formula: EMF = -N x (ΔΦ/Δt), where N is the number of turns and ΔΦ/Δt is the average rate of change of magnetic flux.

Given: N = 1 (single loop), 

ΔΦ/Δt = (Φ₂ - Φ₁) / Δt = (B₂A - B₁A) / Δt, 

B₁ = 0.5 T,

B₂ = 0 T, 

A = πr², 

r = 0.1 m, 

Δt = 0.2 s

   Substituting the values into the formula:

   EMF = -1 x ((0 - 0.5 T) x π x (0.1 m)²) / 0.2 s

       = -1 x (-0.0157 V)

       = 0.0157 V

The average induced EMF in the loop is 0.0157 V.