A semicircle arch of radius a is charged uniformly and the charge per unit length is λ. The electric field at the centre would be:

Consider two uncharged capacitors of equal capacitance 200 pF. One of them is charged by a 100 V supply and disconnected. Now this capacitor is connected to the uncharged capacitor. The amount of electrostatic energy lost in the process is:

Four capacitors C1 = C2 = C3 = C4 = 10 μF are connected in a bridge network, and a fifth capacitor C5 = 2.5 μF is connected across the bridge terminals with a 50 V battery attached. The equivalent capacitance and the charges on each capacitor respectively are: