A potentiometer circuit is set up as shown. The potential gradient, across the potentiometer wire, is k volt/cm and the ammeter, present in the circuit, reads 1.0 A when two way key is switched off. The balance points, when the key between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be at length $$l$$₁ cm and $$l$$₂ cm respectively. The magnitudes, of the resistors R and X, in ohms, are then, equal, respectively, to

See the electrical circuit shown in this figure. Which of the following equations is a correct equation for it ?

A wire of resistance 12 ohms per meter is bent to form a complete circle of radius 10 cm. The resistance between its two diametrically opposite points, A and B as shown in the figure is

The mean free path of electrons in a metal is 4 $$ \times $$ 10^$$-$$8 m. The electric field which can give on an average 2 eV energy to an electron in the metal will be in units V/m