The V - I graphs for two resistors and their series combination are shown in Fig 5.23. Which one of these graphs represents the series combination of the two resistors? Given reason for your answer.

Explanation

From Fig. 5.23,
`R_1 = (V)/(I_1), R_2 = (V)/(I_2), R_3 = (V)/(I_3)`
Since`I_1 lt I_2 lt I_3, So R_1 gt R_2 gt R_3`.
The resistance of the series combination, being the sum of the two resistances, is greater then each of the resistances.
Since `R_1 gt R_2 , R_1 gt R_3`, graph 1 represents the series combination
of the two resistors.