Question

A 100 turn rectangular coil measuring 0.02 m x 0.06 m of an ammeter is in a magnetic field of induction 0.4 tesla. The torsional constant of the suspension fibre is 5 x 10^-7 newton x metre/degree. The maximum reading of the ammeter corresponds to a deflection of the coil through 30°. If the magnetic field is radial, then the maximum current that can be measured with this ammeter is ____________.

Options

• 3.13 x 10^-4 A

• 1.75 x 10^-4 A

• 7.0 x 10^-4 A

• 14.0 x 10^-4 A

Answer 1

A 100 turn rectangular coil measuring 0.02 m x 0.06 m of an ammeter is in a magnetic field of induction 0.4 tesla. The torsional constant of the suspension fibre is 5 x 10^-7 newton x metre/degree. The maximum reading of the ammeter corresponds to a deflection of the coil through 30°. If the magnetic field is radial, then the maximum current that can be measured with this ammeter is 3.13 x 10^-4 A.

Explanation:

`"I" = ("K"phi)/"NAB" = (5 xx 10^-7 xx 30)/(100 xx 0.02 xx 0.06 xx 0.4)`

`therefore "I" = 3.13 xx 10^-4  "A"`