Question

a student performs an experiment and plots the following graph for the two resistors R1 and R2 and there parallel combination which graph represents the parallel combination a b or c

Answer 1

The graph C represents the parallel combination of resistors R1 and R2

1. According to Ohm's Law
2. V=IR here V is voltage , I is current and R is resistance .
3. So the slope of V vs I graph give us Resistance
4. The highest the slope higher the resistance
5. As we know that resistance in parallel combination decreases  
6. Formula to calculate parallel combination of resistance $\frac{1}{Rp} =\frac{1}{R1}+\frac{1}{R2}$
7. In the given figure the slope of A is more than slope B is high and slope of C is low
8. It means the C has lowest resistance so the C is the parallel combination of resistors R1 and R2