You're an electrical engineer designing an alternator (the generator that charges a car's battery). Mechanical engineers specify a 10-cm-diameter rotating coil, and you determine that you can fit 250 turns in this coil. To charge a 12-V battery, you need a peak output of 14 V when the alternator is rotating at 1900 rpm. What do you specify for the alternator's magnetic field?

The alternator's magnetic field is 0.036 T

Explanation:

The area of the rotating coil is equal:

Where

d = 10 cm = 0.1 m

The angular frequency is:

w = 1900 rpm = 198.97 rad/s

The emf is equal:

Where

E = 14 V

N = 250 turns

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