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

Consider the following two statements.
(A)  Kirchoff's junction law follows from the conservation of charge.
(B)  Kirchhoff's loop law follows from the conservation of energy.

Which of the following is correct?

A student measures the terminal potential difference (V) of a cell (of emf $$\varepsilon $$ and internal resistance r) as a function of the current (I) flowing through it. The slope, and intercept, of the graph between V and I, then respectively, equal

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