A current of 1A is flowing along positive x-axis through a straight wire of length 0.5m placed in a region of a magnetic field given by `vec(B)= (2 hat(i) + 4hat(j))`T. The magnitude and the direction of the force experienced by the wire respectively are

Options

A. `sqrt(18)N` , along positive z-axis
B. `sqrt(20)`N , along positive x-axis
C. 2N , along positive z-axis
D. 4N , along positive y-axis

Answer

C

Explanation

`dvecl = 0.5 hati`
`vecB = (2hati + 4hatj) I`
`vecF = I (dvecl xx vecB) = 1 [0.5 hati xx (2hati xx 4 hatj)] = 0 + 2hatk`
F = 2 N along +ve z-axis