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(Be clear and concise. Typing work is strongly suggested. Will thumb up based on

ID: 1423828 • Letter: #

Question

(Be clear and concise. Typing work is strongly suggested. Will thumb up based on the quality of the answer given.) A planar loop consisting of four turns of wire, each of which encloses 200 cm^2, is oriented perpendicularly to a magnetic field that increases uniformly in magnitude from 10 mT to 25 mT in a time of 5.0 ms. What is the resulting induced current in the coil if the resistance of the coil is 5.0 Q? (Give your answer in mA) At what frequency should a 200-tum, flat coil of cross sectional area of 300 cm^2 be rotated in a uniform 30-mT magnetic field to have a maximum value of the induced emf equal to 8.0 V?

Explanation / Answer

here,

1A)

area of the loop , a = 0.02 m^2

change in magnetic feild , delta B = 0.025 - 0.01 T = 0.015 T

time taken , t = 0.005 s

the induced emf , EMF = change in flux /time taken

EMF = a * delta B /delta t

EMF = 0.02 * 0.015 /0.005

EMF = 0.06 V

resistance , r = 5 ohm

induced current , I = EMF /r

I = 0.06/5 = 0.012 A

I = 12 mA

the resulting induced current is 12 mA

1B)

number of turns , n= 200

cross sectional area , a = 0.03 m^2

magnetic feild , B = 0.03 T

EMF = 8 V

let the frequency be f

EMF = 2 * pi * f * n * a * B

8 = 2 * pi * f * 200 * 0.03 * 0.03

f = 7.08 Hz

the frequency needed is 7.08 Hz