A potentiometer wire has length 4 m and resistance 8 $$\Omega $$. The resistance that must be connected in series with the wire and an accumulator of e.m.f. 2 V, so as to get a potential gradient 1 mV per cm on the wire is

The resistances in the two arms of the meter bridge are 5 $$\Omega $$ and R$$\Omega $$ respectively. When the resistance R is shunted with an equal resistance, the new balance point is at 1.6$$l$$₁. The resistance R is

A potentiometer circuit has been set up for finding the internal resistance of a given cell. The main battery, used across the potentiometer wire, has an emf of 2.0 V and a negligible internal resistance. The potentiometer wire itself is 4 m long. When the resistance R, connected across the given cell, has values of (i) infinity,    (ii) 9.5 $$\Omega $$
the balancing lengths on the potentiometer wire are found to be 3 m and 2.85 m, respectively. The value of internal resistance of the cell is

Two cities are 150 km apart. Electric power is sent from one city to another city through copper wires. The fall of potential per km is 8 volt and the average resistance per km is 0.5 $$\Omega $$. The power loss in the wire is