Question

consider the scale of voltmeter shown in the diagram and answer the following questions what is the least count of voltmeter what is the reading shown by voltmeter is this voltmeter is connected across a resistance 20 ohm how much current is flowing through the resistor​

Answer 1

Request to ask a complete question. well I got the complete as shown in figure.

solution : (a) least count of voltmeter = range/number of divisions on voltmeter scale

here, range = (1.5 - 0)= (3.0 - 1.5)= 1.5

number of divisions on voltmeter scale = 10

so, least count of voltmeter = 1.5/10 = 0.15

(b) reason of voltmeter = main scale + n × least count

here, main scale = 1.5V , n = 2 and least count = 0.15

so, reading of voltmeter = 1.5 + 2 × 0.15

= 1.5 + 0.3 = 1.8V

(c) reading of voltmeter is 1.8V

resistance of resistor is 20 ohms.

from Ohm's law,

V = IR => I = V/R = 1.8/20 = 0.09A

Answer 2

Given:

Resistance R=20 ohm

To find:

The least count.

Voltage reading.

Current across the circuit.

Solution:

The least count is

=3/20

=0.15 V

Now the voltmeter reading

(1.5+0.15+0.15)=1.8 V

Now the current

Using the ohm's law.

V=IR

Putting the above value.

I=V/R

I=1.8/20

I=0.09 A

So the answers are least count is 0.15V

Voltmeter reading=1.8V

Current flowing is I=0.09A