A straight wire of mass 200 g and length 1.5 m carrying a current of 2 A is placed in a uniform magnetic field at right angles to its direction, is suspended in mid air. The magnitude of magnetic field is: (g = 9.8 m/s²)

0.65 T

The correct answer is Option (1) → 0.65 T

The force on a current carrying conductor (k).

$F=ILB$ [By Lorentz force]

where,

I, current in the wire = 2A

L, length of wire = 1.5 m

B, magnetic field strength

and,

Mass of wire = $200 g = 0.2 kg$

$mg=ILB$ (given)

$B=\frac{mg}{IL}=\frac{0.2×9.6}{2×1.5}=\frac{9.6}{15}$

$B=0.65T$