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
The thermo emf of a thermocupule varies with the temperature θ of the hot junction as E= aθ +bθ2 volt Where the ratio (a/b) is 700 °C. If the cold junction is kept at 0 °C, then the neutral temperature is
Carbon, silicon and germanium are semiconductors having four valance electrons. If their respective band gap energies between conduction and valence band are (Eg)C, (Eg)Si, (Eg)Ge. Then