Class 12 Physics| Chapter 18| Magnetic field| Problem 18.5| Sindh text book|

To convert a galvanometer into a voltmeter, a high resistance is connected in series with the galvanometer. The value of this resistance is calculated based on the desired range of the voltmeter.
Formula to Find the Resistance
The resistance required for the conversion is given by:
R = \frac{V}{I_g} - G
Where:
= Required resistance in series
= Maximum voltage to be measured (range of the voltmeter)
= Full-scale deflection current of the galvanometer
= Internal resistance of the galvanometer
Steps to Calculate Resistance:
1. Determine the galvanometer parameters:
Find the full-scale deflection current of the galvanometer.
Measure or find the internal resistance of the galvanometer.
2. Choose the range of the voltmeter :
Decide the maximum voltage you want the voltmeter to measure.
3. Substitute into the formula:
Use the formula to calculate the value of the resistance.
4. Connect the resistance:
Connect the calculated resistance in series with the galvanometer
Example:
Let’s say:
Then:
R = \frac{10}{1 \times 10^{-3}} - 50 = 10000 - 50 = 9950 \, \Omega
So, a resistance of should be connected in series with the galvanometer to convert it into a voltmeter with a range of .

[@Babar.attari26]

Sir galvanometer ko voltmeter mi convert krny k lye series mi resistance use krty hn ??

[@ProfessorBabarBashir26]

Yes