Question

A conducting rod of mass $m$ and length $l$ is free to move without friction on two parallel long conducting rails, as shown below. There is a resistance $R$ across the rails. In the entire space around, there is a uniform magnetic field $B$ normal to the plane of the rod and rails. The rod is given an impulsive velocity $v_0$. Finally, the initial energy $\frac{1}{2}m{v}_0^2$

• A. Will be converted fully into heat energy in the resistor
• B. Will enable rod to continue to move with velocity $v_0$ since the rails are frictionless
• C. Will be converted fully into magnetic energy due to induced current
• D. Will be converted into the work done against the magnetic field

Answer 1

Answer: (A)

Will be converted fully into heat energy in the resistor

Magnetic force equals to $F=ilB$ ,will act opposite to the direction of $v_o$.The reduce in kinetic energy will be converted into heat energy by resistor.