A straight wire of mass 200 g and length 1.5 m carries a current of 2 A. It is suspended in mid-air by a uniform horizontal magnetic field B. What is the magnitude of the magnetic field?

Options

A. 2
B. `1.5`
C. `0.55`
D. `0.67`

Answer

D

Explanation

For the equilibrium of the wire in mid air, the weight of the wire acting downsards= upwards force exerted by the magnetic field.
`mg =Bil sin 90^(@)" "[theta =90^(@)]`
`therefore B=(mg)/(Il) =(200xx10^(-3) xx10)/(2xx1.5)div0.67T`