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 (in Ampere)	0.2	0.4	0.6	0.8	1.0

From observation table the resistance in the circuit is
A. $2.5 \Omega$
B. $2\Omega$
C. $5\Omega$
D. $3\Omega$

Answer 1

Hint: Use Ohm's law. It shows the relationship between voltage, current and resistance in an electric circuit. Ohm's law states that the current passing through a conductor between two points is directly proportional to the voltage across two points. Substitute the given values in that formula and calculate the resistance.

Complete step by step answer:
According to Ohm's Law,
$V=IR$
Where, V is the potential difference across the conductor
             I is the current flowing through the resistor
             R is the resistance
Rearranging the above equation we get,
$R= \dfrac {V}{I}$
Substituting each value of potential difference and current in the above equation we get,
$R= \dfrac {0.5}{0.2}$
         $\therefore R= 2.5\Omega$
$R= \dfrac {1.0}{0.4}$
         $\therefore R= 2.5\Omega$
$R= \dfrac {1.5}{0.6}$
         $\therefore R= 2.5\Omega$
$R= \dfrac {2.0}{0.8}$
         $\therefore R= 2.5\Omega$
$R= \dfrac {2.5}{1.0}$
         $\therefore R= 2.5\Omega$
Thus, the resistance in the circuit is $2.5\Omega$.
Hence, the correct answer is option A i.e. $2\Omega$.

Note:
Current-Voltage relationship is generally represented in the form of graphs. Voltage is plotted along the X-axis of the graph and current is plotted along the Y-axis of the graph. Voltage versus current graph gives a straight line and has a constant slope. If the conductor has a constant slope in current versus voltage graph then it is called a Ohmic Conductor. But if the conductor does not obey Ohm's law and the resistance is not constant then the conductor is called Non-ohmic conductor.
The graph for the given table is shown below: