EMF Example

A wire 40 cm long bent into a rectangular loop of 15 cm x 5 cm is placed perpendicular to the magnetic field whose flux density is 0.8Wbm². Within 0.5 seconds, the loop is changed into a 10cm square and the flux density increases to 1.4 Wb m^-². Find the induced EMF.

Sub Topics

Suggested solution:

Suggested solution:

Initial area,

A₁ = 15 cm x 5 cm = 75 cm² = 75 x 10^-⁴ m²

Initial magnetic flux density,

B₁ = 0.8 Wb m^-²

Initial magnetic flux,

f₁ = B₁A₁ = 0.8 x 75 x 10^-⁴ Wb = 60 x 10^-⁴ m²

Final area,

A₂ = 10cm x 10 cm = 100cm² = 100 x 10^-⁴ Wb

Final magnetic flux density,

B₂ = 1.4 Wb m^-²

Final magnetic flux,

f₂ = B₂A₂ = 1.4 x 100 x 10^-⁴ Wb

= 140 x 10^-⁴ Wb

Change in magnetic flux,

df = f₂ - f₁ = (140 x 10^-⁴ - 60 x 10^-⁴ ) Wb

Induced EMF