50. Resistance of a conductor of diameter and length L is R ohm. It the diameter of the conductor is halved and its length is doubled the resistance will be-.
ব্যাখ্যা: A battery is a device that stores electric power in the form of chemical energy. When necessary the energy a again released as electric power for DC consumers such as lighting and starter motors.
58. Two charged spheres of radii 10cm and 15cm are connected by a thin wire. No current will flow if they have-
ব্যাখ্যাঃ The current flows from higher potential to lower pontential. And if the potential difference is zero, then no current flows through the wire.