Question

While studying the dependence of potential difference(V) across a resistor on the current(I) passing through it, in order to determine the resistance of a resistor, a student took 5 readings for different values of current and plotted a graph between V and I. He got a straight-line graph passing through the origin. What does the straight line signify? Write the method of determining resistance of the resistor using this graph.(All India - 2019)

Answer 1

We can determine the resistance of the resistors used by the student from the graph plotted by him by following the simple steps :-

(I) Mark or name the points on the graph for which the potential difference changes with respect to the different resistors used.

(II) Say at any point A, we need to find the value of the resistance of the resistor used by the student. we will Divide the value of coordinates of the y axis with the x axis. For example, let at point A, 4 ampere current was taken with 8 volts of potential difference. so, we will Divide 8/4.

(III) we will get the value of slope of the graph by dividing 8/4 which will give us 2 ohm as the resistance as we know that V=IR ( FROM OHM'S LAW), so V/I will give us the value of the resistance of the resistor used by the student.

Using this few steps,we can find the value of resistance of the resistor used by the student easily.

Also,the straight-line graph passing through the origin indicates that the change in potential difference with respect to the change in current passing through is uniformly increasing or constant.

For example - At the point A it was 2 ohm,

At point B it will be also 2 ohm and So on if the graph has straight line passing through the origin

I hope you liked the answer. If it helps make sure to mark it as brainliest.

Have a nice day ahead :)

Answer 2

Answer:

When the student took 5 readings for different values of R and the student gets a straight line graph.

This verifies Ohm's law.

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points

So, if you plot a graph of current against voltage you will get :

I∝V

I=

R

V

R=

I

V