A coil in the shape of an equilateral triangle of side 0.02 m is suspended from its vertex such that it is hanging in a vertical plane between the pole pieces of permanent magnet producing a uniform field of 5 × 10-2 T. If a current of 0.1 A is passed through the coil, what is the couple acting?

Question

A coil in the shape of an equilateral triangle of side 0.02 m is suspended from its vertex such that it is hanging in a vertical plane between the pole pieces of permanent magnet producing a uniform field of 5 × 10-2 T. If a current of 0.1 A is passed through the coil, what is the couple acting? (A) 5 √ 3 × 10-7N-m  (B) 5 √ 3 × 10-10N-m  (C)  (√ 3/5) × 10-7 N-m  (D) None of these

Tardigrade Admin · Accepted Answer

Torque τ=i A B sin θ, i=0.1 A, θ=90° A=(1/2) × base × height or A=(1/2) a × (a √3/2) =(√3 a2/4)=(√3 ×(0.02)2/4) =√3 × 10-4 m2 ; θ=90° τ=0.1 × √3 × 10-4 × 5 × 10-2 sin 90° =5 √3 × 10-7 N-m

$53 \times 1 0^{- 7} N - m$

$53 \times 1 0^{- 10} N - m$

$\frac{3}{5} \times 1 0^{- 7} N - m$

None of these

Q. A coil in the shape of an equilateral triangle of side 0.02m is suspended from its vertex such that it is hanging in a vertical plane between the pole pieces of permanent magnet producing a uniform field of 5×10−2T. If a current of 0.1A is passed through the coil, what is the couple acting?

53​×10−7N−m

53​×10−10N−m

53​​×10−7N−m

None of these

Torque τ=iABsinθ,i=0.1A,θ=90∘ A=21​× base × height or A=21​a×2a3​​ =43​a2​=43​×(0.02)2​ =3​×10−4m2;θ=90∘ τ=0.1×3​×10−4×5×10−2sin90∘ =53​×10−7N−m

$53 \times 1 0^{- 7} N - m$

$53 \times 1 0^{- 10} N - m$

$\frac{3}{5} \times 1 0^{- 7} N - m$