Question

A straight conducting rod of length l and mass m is suspended in a horizontal plane by a pair of flexible strings in a magnetic field of magnitude B. To remove the tension in the supporting strings, the magnitude of the current in the wire is ______.

विकल्प

• `(mgB)/l`

• `(mgl)/B`

• `(mg)/(lB)`

• `(lB)/(mg)`

Answer 1

A straight conducting rod of length l and mass m is suspended in a horizontal plane by a pair of flexible strings in a magnetic field of magnitude B. To remove the tension in the supporting strings, the magnitude of the current in the wire is `bbunderline((mg)/(lB))`.

Explanation:

F = mg = T

Magnetic force = F_mag = ilB

To remove the tension,

T = F_mag

or, mg = ilB

∴ `i = (mg)/(lB)`

To remove the tension,

T = F_mag

or, mg = iLB

∴ `i = (mg)/(LB)`