Basic Galvanometer

The current sensitivity of the galvanometer is given as

10%20%5Cmu%20A%2F%5Ctext%7Bdiv%7D

and it has 20 divisions, so the full-scale deflection current is:

I_%7B%5Ctext%7Bfull%20scale%7D%7D%20%3D%2010%20%5C%2C%20%5Cmu%20A%20%5Ctimes%2020%20%3D%20200%20%5C%2C%20%5Cmu%20A

Next, to convert the galvanometer into a voltmeter, we need to find the resistance needed to allow the galvanometer to measure up to 1V. According to Ohm's law:

V%20%3D%20I%20%5Ctimes%20R

Where

V%20%3D%201%20%5C%2C%20%5Ctext%7BV%7D

and

I%20%3D%20200%20%5C%2C%20%5Cmu%20A%20%3D%20200%20%5Ctimes%2010%5E%7B-6%7D%20%5C%2C%20%5Ctext%7BA%7D

. Thus:

R_%7B%5Ctext%7Btotal%7D%7D%20%3D%20%5Cfrac%7BV%7D%7BI%7D%20%3D%20%5Cfrac%7B1%20%5C%2C%20%5Ctext%7BV%7D%7D%7B200%20%5Ctimes%2010%5E%7B-6%7D%20%5C%2C%20%5Ctext%7BA%7D%7D%20%3D%205000%20%5C%2C%20%5COmega

The resistance of the galvanometer is already

100%20%5C%2C%20%5COmega

, so the additional resistance

R

required in series is:

R%20%3D%20R_%7B%5Ctext%7Btotal%7D%7D%20-%20R_%7B%5Ctext%7Bgalv%7D%7D%20%3D%205000%20%5C%2C%20%5COmega%20-%20100%20%5C%2C%20%5COmega%20%3D%204900%20%5C%2C%20%5COmega

Thus, the resistance required is

49000%20%5C%2C%20%5COmega

in series with the galvanometer to convert it into a voltmeter reading up to 1 V.

High-Yield Trend

Chapter Questions
1 MCQs

Official Solution

Basic Galvanometer

High-Yield Trend

Chapter Questions 1 MCQs

Official Solution

Chapter Questions
1 MCQs