A coil in the shape of an equilateral triangle of side 2 cm is suspended from a vertex such that it hangs in a vertical plane between the poles of a permanent magnet producing a horizontal magnetic field of 100 `xx 10^(-3)` T. the
magnetic field is parallel to the plane of the coil. for the moment of cuple acting on the coil to be `2sqrt(3) xx 10^(-5)` Nm, the current to be passed through the coil is

Options

A. 0.5 A
B. `1 A`
C. `2 A`
D. `4 A `

Answer

B

Explanation

Given, magnetic field, B = 100 `xx 10^(-3)` T
Torque , `tau = 2sqrt(3) xx 10^(-5) ` Nm
Now, torque `tau `= MB = IAB
where, M = magneitc dipole moment,
B = mgnetic field
I = current to be passed through the coil .
putting the given values in above expression,
`2 sqrt(3) xx 10^(-5) = I x sqrt(3) xx 10^(-4) xx 100 xx 10^(-3) or I 2A `