The smallest value that can be measured is called Least Count .

 

In Ammeter and Voltmeter, the smallest value that can be measured will be least count.

Let's do this by some examples

 

Find Least count of Ammeter and Voltmeter given below

 

Finding Least Count of Ammeter and Volmeter - Example 1 - Teachoo.png

Here,

Voltmeter Ammeter

For Voltmeter, 

We see that

5 Division is equal to 2 Volts

 

So, 

Least Count = 2/5

= 0.4 V

For Ammeter, 

We see that

5 Division is equal to 10 Amperes

 

So, 

Least Count = 10/5

= 2 A

 

So, Least Count of Voltmeter is 0.4 V and Least count for Ammeter is 2A

 


Find Least count of Ammeter and Voltmeter given below

Finding Least Count of Ammeter and Volmeter - Example 2 - Teachoo.jpg

 

 

Voltmeter Ammeter

For Voltmeter, 

We see that

10 Divisions is equal to 5 Volts

 

So, 

Least Count = 5/10

= 0.5 V

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

 

So, Least Count of Voltmeter is 0.5 V and Least count for Ammeter is 0.01 A

 


Find Least count of Ammeter and Voltmeter given below

 

Find least count of Ammeter and voltmeter Example 3 - Teachoo.jpg

 

Ammeter Voltmeter

For Ammeter, 

We see that

10 Divisions is equal to 0.2 Amperes

 


So, 

Least Count = 0.2/10

= 0.02 A

For Voltmeter, 

We see that

10 Division is equal to 1 Volt

 

So, 

Least Count = 1/10

= 0.1 V

 

So, Least Count of Voltmeter is 0.4 V and Least count for Ammeter is 0.02 A

 


An ammeter has a range of 0-3 ampere and there are 30 divisions on its scales. What is its least count?

 

This means that

In Ammeter

30 Division is 3 A

 

So, 

Least Count = 3/30

= 1/10

= 0.1 A

 

So, Least Count of Ammeter is 0.1 A

  1. Class 10
  2. Chapter 12 Class 10 - Electricity

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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.