Answer Happy

11. A rod of mass 0.72 kg and radius 0.06 m rests on two parallel rails that are d = 0.12 m apart and L = 0.45 m long. The rod carries a current of I = 48 A. If it starts from rest, what is the speed of the rod as it leaves the rails if there is a uniform magnetic field of magnitude 0.24 T directed perpendicular to the rod and rails? Answer in units of m/s.
a 12. A capacitor of capacitance C = 500uF is charged to a voltage of 900 V and is then discharged through a resistance R = 200 kA when a switch is closed. (1) Find the initial charge stored in the capacitor. (ii) Find the initial discharge current when the switch is closed. (iii) Find the voltage across the capacitor in a time t = 25 s after the start of discharge. (iv) Find the time constant of this capacitor resistor network combination.