NEETPhysicsCurrent Electricity
The voltage-current ( V-I ) characteristics of two combinations of N identical resistors are plotted on a graph with voltage on the Y-axis and current on the X-axis. The straight line representing the series combination of these resistors passes through the coordinate (2 A , 18 V ) . The straight line representing the parallel combination of the same resistors passes through the coordinate (3 A , 3 V ) . The number o
Options
- A9
- B81
- C3
- D6
Correct answer
C. 3
Step-by-step solution
From the V-I graph (with voltage on the Y-axis and current on the X-axis), the resistance is given by the slope of the line, R = V I . For the series combination, the equivalent resistance R_s is: R_s = 18 2 = 9 For the parallel combination, the equivalent resistance R_p is: R_p = 3 3 = 1 If there are N identical resistors each of resistance R , then their series equivalent is R_s = NR and their parallel equivalent is R_p = R N . Taking the ratio of the two equivalent resistances: R_s R_p = NR R N = N^2 Substitutin