Square Ammeter Coil (1 Viewer)

[MrLuvable]

An square ammeter coil has 80 turns of wire each of area 16.0cm^2. It is pivoted in a radial magnetic field of intensity 0.25T.
a) Calculate the magnitude of toque acting on the coil when 60mA flows through it.

My Working:

Torque = nBIACosθ
= 80 x 0.25 x 0.06 x (0.16)^2
= 0.03072

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The books answer states that the magnitude of the torque is 1.92x10^-3

Can anyone tell me where I'm going wrong, or is the books answer wrong?
Thanks

 

[P!xel]

Torque = nBIAcosθ

n = 80
B = 0.25
I = 0.060
A = 0.0016
θ = 0

= 80 x 0.25 x 0.060 x 0.0016 x 1
= 1.92x10^-3 Nm

Note that the area is given, therefore you don't need to square it again.
And you should convert the area into m^2.

 

[MrLuvable]

Ah ! Thanks Silly mistake on my half.