A uniform magnetic field parallel to the plane of paper, exsisted in space initially directed from left to right. When a bar of soft iron is placed in the field parallel to it, the lines of force passing through it will be represented by figure.
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