In a Wheatstone's bridge all the four arms have equal resistance R. If the resistance of the galvanometer arm is also R, the equivalent resistance of the combination as seen by the battery is

For a cell terminal potential difference is 2.2V when circuit is open and reduce to 1.8 V when cell is connected to a resistance of R = 5 $$\Omega $$. Determine internal resistance of cell (r)

Specific resistance of a conductor increases with

Copper and silicon is cooled from 300 K to 60 K , the specific resistance