Question

A horizontal wire of mass 'm', length 'l' and resistance 'R' is sliding on the vertical rails on which uniform magnetic field 'B' is directed perpendicular. The terminal speed of the wire as it falls under the force of gravity is ($g =$ acceleration due to gravity)

• A. $\frac{mgl}{BR}$
• B. $\frac{B^{2}l^{2}}{mgR}$
• C. $\frac{mgR}{Bl}$
• D. $\frac{mgR}{B^{2}l^{2}}$

Hint:

Physics Tip: Terminal velocity occurs when the magnetic braking force (proportional to velocity) perfectly balances the constant gravitational force.

Answer 1

The Correct Option is D