Question

In an experiment of verification of Ohm’s Law, following observations are obtained:

Potential difference V (in volt)	0.5	1.0	1.5	2.0	2.5
Current I (in ampere)	0.2	0.4	0.6	0.8	1

What will be current I when the potential difference V is 0.75 V?
A. 0.5 A
B. 0.3 A
C. 0.75 A
D. 0.6 A

Answer 1

Hint: Question involving such data can easily be solved by using the 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” or $P=IR$

Formula used:
The formula that we will be using to solve the given question is Ohm’s Law, i.e., $V=IR$

Complete answer:
From the above given observation, we can find out the resistance of the conductor.
Let the resistance be R
By Ohm’s Law, we know that
$V=IR$
Now for finding the value of R, we can take the data from any column of the observation table.
For example, let us take $V=0.5V$and $I=0.2A$
So,
$R=\dfrac{V}{\begin{align}
  & I \\
 & \\
\end{align}}$
$R=\dfrac{0.5}{0.2}=\dfrac{5}{2}$
$R=2.5\Omega $
For to find the current when the potential difference $V=0.75V$
Again, using Ohm’s Law
 $V=IR$
$\implies I=\dfrac{V}{R}$
\[I=\dfrac{0.75}{2.5}=0.3A\]
$I=0.3A$
So, the current flowing through the conductor when the potential difference is 0.75V will 0.3A

Note:
You can also solve this problem by using the graph made from the observation table

In the above graph, we can see the observation table gives data which forms a straight line. Now, we can say that the slope of this line will be equal to the resistance R of the conductor.
Since, the slope of a straight line (resistance) remains constant
$\dfrac{{{V}_{1}}}{{{I}_{1}}}=\dfrac{{{V}_{2}}}{{{I}_{2}}}$
So,
$\begin{align}
  & \dfrac{0.75}{I}=\dfrac{0.5}{0.2} \\
 & \\
 & I=\dfrac{0.75}{2.5} \\
 & \\
 & I=0.3A \\
\end{align}$

Therefore, current flowing through the conductor when the potential difference is 0.75V will be 0.3A