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?

The current flowing through a resistor connected - Teachoo.jpg

 

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

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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo