A battery consists of a variable number n of identical cells (having internal resistance r each) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n?

A carbon resistor of (47 $$ \pm $$ 4.7) k$$\Omega $$ is to be marked with rings of different colours for its identification. The colour code sequence will be

A set of n equal resistors, of value R each, are connected in series to a battery of emf E and internal resistance R. The current drawn is I. Now, the n resistors are connected in parallel to the same battery. Then the current drawn from battery becomes 10I. The value of n is

A potentiometer is an accurate and versatile device to make electrical measurements of EMF because the method involves