Question

66. A coil in the shape of an equilateral triangle of side 0.02 m is suspended
such that it is hanging in a vertical plane Between the pole
pieces of a permanent magnet
producing a horizontal fields of 5x 10-2 T. Find the couple
acting on the coil when a
current of 0.1 A is passed through it and the magnetic field parallel its plane is

Answer 1

Torque τ=iABsinθ,i=0.1A,θ=90∘

A=12×base×height

or A=12a×a3√2

=3√a24=3√×(0.02)24

=3–√×10−4m2;θ=90∘

τ=0.1×3–√×10−4×5×10−2sin90∘

=53–√×10−7N−m