A 0.65-T magnetic field is perpendicular to a circular loop of wire with 73 turns and a radius of 18 cm. If the magnetic field is reduced to zero in 0.12 s, what is the magnitude of the induced emf?

40.25 V

Explanation:

Parameters given:

Initial magnetic field, B1 = 0.65 T

Final magnetic field, B2 = 0 T

Number of turns, N = 73

Radius of loop, r = 18 cm = 0.18 m

Time taken, Δt = 0.12 s

The magnitude of the EMF induced in a loop of wire due to a changing magnetic field is given as:

V = | [-N * A * (B2 - B1) ] / Δt |

Where A = area of loop

Area of loop = πr²

Therefore, the magnitude of the EMF induced will be:

V = | [-N * πr² * (B2 - B1) ] / Δt |

V = | [-73 * π * 0.18² * (0 - 0.65) ] / 0.12 |

V = |40.25| V

V = 40.25 V

This is the magnitude of the EMF induced in the loop of wire.