Two straight segments of wire ab and bc each carrying current I, are placed as shown in fig. The cube edge is 50 cm and magnetic field is uniform along y-axis having magnitude 0.4T

Options

A. `0.6hat i`
B. `1.2(hati+hatk)`
C. `0.6(sqrt2hati+hatj-sqrt2hatk)`
D. `0.6(sqrt2hati-hatk)`

Answer

A

Explanation

Wire abc can be replaced by a straight wire ac for the com-
pulation of force.
Length of `vec(ac)` can be written as,
`vecl=vecr_C-vecr_A=[(hati+hatj)-(hati+hatk)]50xx10^-2=0.50[hatj-hatk]`
Required force, `vecF=I(veclxxvecB)=0.6hati`