A magnetic field question?

Question

A wire having a mass per unit length of 0.500 g/cm carries a 2.00-A current horizontally to the south. What is the magnitude of the minimum magnetic field needed to lift this wire vertically upward?

Answer 1

mag lavitation>

F (mag) = weight of wire =mg

let L be length

F (mag) = BIL sin p = mg

B = [m/L] * [g/{I sin p}]

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B = mag field will be minimum, when F(mag) is max >>

or sin p =1

B (min) = [m/L] * [g/{I }] = [0.5*10^-3/10^-2] [9.8/2]

= [0.5*10^-1] [9.8/2]

= 0.245 Tesla