-18.33 points My Notes Ask Your Tescher O A 21-turn circular coil of wire has di

Question

-18.33 points My Notes Ask Your Tescher O A 21-turn circular coil of wire has diameter 1.06 m. It is placed with its axis along the direction of the Earth's magnetic field of 49.0 HT and then in 0.200 s is flipped 180°. An average emf of what magnitude is generated in the coil? mV Submit Answer Save Progress + -8.33 points My Notes Ask Your Teacher A flat loop of wire consisting of a single turn of cross-sectional area 8.40 cm2 is perpendicular to a magnetic field that increases uniformly in magnitude from 0.500 T to 3.50 T in 0.91 s. What is the resulting induced current if the loop has a resistance of 2.60 ? mA Submit Answer Save Progress

Explanation / Answer

First Question -

Write down the expression for magnetic flux -

Magnetic flux = (magnetic field) (area that magnetic field passes through)
= B A = BAcos

Again, magnitude of induced emf = (number of coils)|rate of change of magnetic flux|
= N |d/dt|

Assuming that the rotational speed of the flipping coil is constant,
= N |/t|
= N |[BA - (-BA)]/t|
= 2NBA/t

Now, put the values -
= 2(21)(49x10^-6 T)[(1.06 m / 2)²]/(0.20 s) = 0.00908 V = 9.08 mV

Hence average emf generated = 9.08 mV.  

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