Question

In the shown figure, there are two long fixed parallel conducting rails having negligible resistance) and are separated by distance $L$ . A uniform rod(cd) of resistance $R$ and $\mathrm{mass}M$ is placed at rest on frictionless rail. Now at time $t=0,$ a capacitor having charge $Q_0$ and capacitance $C$ is connected across rails at ends a and b such that current in rod(cd) is from $c$ towards $d$ and the rod is released. A uniform and constant magnetic ficld having magnitude $B$ exists normal to plane of paper as shown. (Neglect acceleration due to gravity) . When the acceleration of rod is zero, the speed of rod is

• A. $\frac{Q_0{R}^{2}BC}{M+B^2{L}^2{C}^2}$
• B. $\frac{Q_{0}LB}{M+B^2{L}^{2}C}$
• C. $\frac{Q_{0}LB}{M+B^2{R}^4{C}^4}$
• D. $\frac{Q_{0}LB}{M+B^2{L}^2{C}^2}$

Answer 1

Answer: (B)