Question

People have proposed driving motors with the earth's magnetic field. This is possible in principle, but the small field means that unrealistically large currents are needed to produce noticeable torques. Suppose a 20-cm-diameter loop of wire is oriented for maximum torque in the earth's field.What current would it need to carry in order to experience a very modest 1.0?

Answer 1

636.619772368 A

Step-by-step explanation:

`\tau` = Torque =
`1* 10^(-3)\ N/m`

B = Magnetic field of Earth =
`5* 10^(-5)\ T`

A = Area

d = Diameter = 20 cm

Current is given by

`I=(\tau)/(BA)\\\Rightarrow I=(1* 10^(-3))/(5* 10^(-5)* (\pi)/(4)* 0.2^2)\\\Rightarrow I=636.619772368\ A`

The current is 636.619772368 A