# Faraday's Law of Induction and Current

#### Kandycat

1. Homework Statement

A 22.0-cm-diameter coil consists of 20 turns of circular copper wire of 2.6 mm in diameter. A uniform magnetic field, perpendicular to the plane of the coil, changes at a rate of 8.65 x 10-3 T/s. Determine (a) the current in the loop, and (b) the rate at which thermal energy is produced.

2. Homework Equations
V = NBA / t
R= pl/A

l = N*2*pi*diameter of coil

I = V/R

3. The Attempt at a Solution

I understand the part (a)... sort of. Tell me if I did it something wrong.

V = NBA / t
V = (20)(8.65 x 10-3 T/s)(pi*(.0013 m)2) = 9.19 x 10-3 V

R = pl/A
R = (1.72 x 10-8)(20*2*pi*.22 m)/ (pi*(.0013 m)2) = 8.96 x 10-2 ohms

I = V/R
I = 9.19 x 10-3 V / 8.96 x 10-2 ohms = 1.03 x 10-5 A

Part (b) I don't understand. I don't know what I'm finding.

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#### rl.bhat

Homework Helper
the rate at which thermal energy is produced.
It is power and is found by P=I^2*R.

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