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The AC voltage across a resistance can be measured using a :

  • Option 1)

     potentiometer
     

  • Option 2)

    moving coil galvanometer

  • Option 3)

    moving magnet galvanometer

     

  • Option 4)

    hot wire voltmeter

 

Answers (1)

As we learnt in 

To determine the resistance of a galvanometer by half deflection method -

G= \frac{RS}{R-S}

G= galvanometre resistance 

R= Extreme resistance

S= Shunt

Procedure

Resistance of galvanometer by half deflection method.

1.    Draw the circuit diagram as shown in figure.

2.    See that plugs of the resistance boxes are tight.

3.    Take out high resistance (2000 \Omega) from the resistance box R and insert the key K1 only.

4.    Adjust the value of R so that deflection is maximum, even in number and within scale. 

5.    Note the deflection. Let it be \theta.

6.    Now, insert the key K2 and without changing the value of R adjust the value of S such that deflection in the galvanometer reduces to exactly half the value obtained in step 5 i.e. \frac{\theta}{2}

7.    Note the value of resistance S.

8.    Repeat steps 4 to 7 three times taking out different values of R and adjusting S every time. 

- wherein

I_{g}\propto \theta

I_{g}=K \theta

\theta= definite angle

Ig  = current passing through galvanometre

K= figuring merit

 

 Moving coil or magnet galvanometer can measure only d.c. values. For A.C. voltage hot wire voltmeter is used.


Option 1)

 potentiometer
 

This option is incorrect

Option 2)

moving coil galvanometer

This option is incorrect

Option 3)

moving magnet galvanometer

 

This option is incorrect

Option 4)

hot wire voltmeter

This option is correct

Posted by

Vakul

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