The internal resistance of primary cell is 4Ω. It generates a current of 0.2 A in an external resistance of 21Ω. The rate at which chemical energy is consumed is providing the current is
There are four point charges +q, -q, +q and –q are places at the corners A, B, C and D respectively of a square of side a. The potential energy of the system is times .
There are N cells in the circuit of figure. The emf and internal resistance of each cell is E and rrespectively. The points A and B in the circuit divide the curit into n and (N-n) cells. The current in the circuit is
The two spherical conductor A and B. of radii a and b(b>a) are placed concentrically in air. The two arc connected by a copper wire as shown in figure. The equivalent capacitance of the system is