Question

A current of 12.5 mA is maintained in a single circular loop with a circumference of 2.55 m. A magnetic field of 0.750 T is directed parallel to the plane of the loop. What is the magnitude of the torque exerted by the magnetic field on the loop

Answer 1

Torque
`= 4.856 * 10^(-3)` Nm

Step-by-step explanation:

Torque can be calculated by using below given relation

`T= BIA` ---------- Equation (1)

Where T is the torque in Nm

B is the magnetic field in Tesla

I is the current in Ampere

and A is the area in square meter

Since the current is flowing in circular loop, its area will be equal to
`A = \pi r^2`

Circumference
`= 2 \pi r`

`2.55 = 2 * 3.14 * r\\r = (2.55)/(2*3.14) \\r = 0.406`

Substituting the value of r in the formula of area we get -

`A = 3.14 * (0.406)^2\\A = 0.518`

Substituting all the values in equation 1

`T= 0.75 * 12.5 * 10^(-3) * 0.518 \\T = 4.856 * 10^(-3)`