Question

A circular coil of 144 turns has a radius of 1.54 cm. (a) Calculate the current that results in a magnetic dipole moment of magnitude 2.13 A

Answer 1

Given :

Magnetic dipole moment ( ? ) = 2.13A.m²
No. of turns N = 144
radius r = 1.54cm = 1.54 x 10^-2 m
Magnetic field B = 37 mT = 37 x 10^-3 T
We know that : ? = NI (?r²) where I is thecurrent in Amperes.
a) Solving for I, we get: I = ? / (N?r²)

                                       = 2.13 A.m² / (144 x ? x 1.54² x 10^-4)

                                        = 2.13 x 10⁴ / (144 x ? x 1.54²)
                                         = 19.85 A
b) Torque is given by ? = ?B = 2.13 x 37x10^-3 = 0.07881 N.m         
Solve it

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