The current flowing through a resistor connected in a circuit and the potential difference developed across its ends are as shown in the diagram by milliammeter and voltmeter readings respectively.
(a) What are the least counts of these meters?
(b) What is the resistance of the resistor?
Answer:
(a)
|
Ammeter |
Voltmeter |
|
For Ammeter, We see that 10 Divisions is equal to 100 Milli Amperes
So, Least Count = 100/10 mA = 10 mA = 10 × 10 -3 A = 10 -2 A = 0.01 A |
For Voltmeter, We see that 10 Divisions is equal to 1 Volt
So, Least Count = 1/10 = 0.1 V |
(b)
According to ohm’s law,
Resistance = V / I
Resistance = Reading of voltmeter / reading of ammeter
= 2.4 Volts / 250 mA
= 2.4 Volts / 250 * 10 -3 A
= 2.4 Volts / 0.25 A
= 9.6 ohm