. There exists a uniform magnetic field in horizontal direction perpendicular to the plane of the paper as shown in the figure.

There exists a uniform magnetic field in horizontal direction perpendicular to the plane of the paper as shown in the figure. A wire of length l is attached with a block of equal mass with the help of an ideal string. The block is kept on floor and the wire on two conducting support as shown. After closing the switch a charge q passes through the wire for a small interval of time. To what height block will rise (take  SI units g = 10 m/s²)