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Question
The values of current I flowing in a given resistor for the corresponding values of potential difference V across the resistor are given below:
| I (amperes) | 0.5 | 1.0 | 2.0 | 3.0 | 4.0 |
| V (volts) | 1.6 | 3.4 | 6.7 | 10.2 | 13.2 |
Plot a graph between V and I and calculate the resistance of that resistor.
Solution
The plot between voltage and current is called IV characteristic. The voltage is plotted on x-axis and current is plotted on y-axis. The values of the current for different values of the voltage are shown in the given table.
| V (volts) | 1.6 | 3.4 | 6.7 | 10.2 | 13.2 |
| I (amperes) | 0.5 | 1.0 | 2.0 | 3.0 | 4.0 |
The IV characteristic of the given resistor is plotted in the following figure.
For V = 4 V (i.e., 9 V − 5 V)
I = 1.25 A (i.e., 2.65 A − 1.40 A).
∴ `"R" = "V"/"I"`
= `(4 "V")/(1.25 "A")`
= 3.2 Ω
The accuracy of the graph's plotting determines the value of R that is found on it.
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