Question

The graph between current $\left(I\right)$ and potential difference $\left(V\right)$ in the experimental verification of Ohm's Law drawn by four students. Which one is correct?

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The correct option is B

Explanation for correct options:

In case of option B,

1. According to the Ohm's law, “the potential $\left(V\right)$ across a conductor is directly proportional to the current $\left(I\right)$ through it, provided all the physical conditions and temperature remains constant.” That is $V\propto I$.
2. It can be further expressed as $V=IR$, where $R$, the resistance, is the proportionality constant.
3. So, it is clear that with the increase in voltage, the current will increase proportionally.
4. Therefore, the graph obtained will be a straight line, which is increasing in nature.

Explanation for incorrect options:

In the case of option A,

1. The given graph is a straight line but is decreasing in nature.
2. It shows that the current is decreasing with the increase in voltage.
3. According to this, the current is inversely proportional to voltage $I\propto \frac{1}{V}$, which is false.
4. Thus, this option is incorrect.

In the case of option C,

1. The given graph states that with the increase in current, the value of voltage remains constant.
2. But according to Ohm's law, the current and voltage are directly proportional to each other.
3. Thus, this option is incorrect.

In the case of option D,

1. The given graph states that with the increase in voltage, the value of current remains constant.
2. But according to Ohm's law, the current and voltage are directly proportional to each other.
3. Thus, this option is incorrect.

Hence, option B is correct.