What is the emf induced in the coil?

Question

A 30-turn, 10-cm-diameter coil is oriented in a vertical plane with its axis aligned east-west. A magnetic field pointing to the northeast decreases from 0.72T to 0.26T in 2.4s.

What is the emf induced in the coil?

Answer 1

The change in magnetic flux is:

∆Φ = ∆BA cos θ

= (0.26 T - 0.72 T) x (π x (0.05 m)²) x cos(45°)

= - 2.5 mWb

The induced emf is:

Ɛ = - N∆Φ / ∆t

= (30 turns x (2.5 x 10^-3 Wb)) / 2.4 s

= 3.1 cV