The figure (1) shows the experimental set up for verification of Ohm’s law. Graph obtained for this set up is shown in figure (2). If the resistance R is changed with a new resistance of value 2R and the experiment is repeated again then which of the following will be the correct V-I graph?    

 

 

 

 

 

 

 

Even if resistance R is changed with 2R, according to Ohm’s law V is still proportional to I i.e., the graph between V and I is a straight line. Then why option (a) is not correct? Because the slope of V.I. graph gives the value of resistance. As the value of resistance is increased from R to 2R, the slope of given graph must also increase which is shown in fig. (d).