Answer:
Maximum speed of the rod, v = 10.34 m/s
Explanation:
It is given that,
Voltage of the battery, V = 2.7 V
The magnetic field perpendicularly into the plane of the paper is, B = 0.9 T
Length of the rod between the rails, l = 0.29 m
Due to the motion of the rails inside the magnetic field, an emf will induced in it which is given by :

v is the speed attained by the rod



v = 10.34 m/s
So, the maximum speed attained by the rod after the switch is closed is 10.34 m/s. Hence, this is the required solution.