Question

A straight wire of length 50 cm carrying a current of 6 A is suspended in mid-air by a uniform magnetic field of 0.4 T (as shown in figure). The mass of the wire is ______.

(g = 10` "ms"^-2`)

Options

• 0.12 g

• 125 g

• 62.5 g

• 100 g

Answer 1

A straight wire of length 50 cm carrying a current of 6 A is suspended in mid-air by a uniform magnetic field of 0.4 T (as shown in figure). The mass of the wire is 0.12 g.

Explanation:

F = `"I"/"B"` sin `theta`

`theta` = `90^circ`

`therefore "sin"  90^circ` =1

`therefore "F" = "I"/"B"`

`therefore "mg" = "I"/"B"`

m = `("I"/"B")/"g"`

= `(6xx50xx10^-2xx0.4)/10` = 0.12 g