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Which of the following statements is false ?
 

  • Option 1)

     

     Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.

     

  • Option 2)

    In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.

     

  • Option 3)

    A rheostat can be used as a potential divider.

                

  • Option 4)

     Kirchhoff’s second law represents energy conservation.

        

 

Answers (2)

best_answer

As we learnt in 

To find resistance of a given wire using metre bridge and hence determine the specific resistance -

For unknown resistance

X=\frac{\left (100 - l\right )R}{l}

x= Unknown resistance 

R= Given resistance

 

- wherein

Calculation

\rho = \frac{X\pi D^{2}}{4l}

= .........ohms

\rho = Resistivity

X = Unknown resistance

D = Diametre

L = length of wire

 

 

 

There is no change in null point, if the cell and the galvanometer are exchanged in a balanced bridge. 

So, option (2) is the answer

Balancing condition 

\frac{R_{1}}{R_{3}}=\frac{R_{2}}{R_{4}}

Balancing condition 

\frac{R_{1}}{R_{2}}=\frac{R_{3}}{R_{4}}

 


Option 1)

 

 Wheatstone bridge is the most sensitive when all the four resistances are of the same order of magnitude.

 

Incorrect 

Option 2)

In a balanced wheatstone bridge if the cell and the galvanometer are exchanged, the null point is disturbed.

 

Correct 

Option 3)

A rheostat can be used as a potential divider.

            

Incorrect 

Option 4)

 Kirchhoff’s second law represents energy conservation.

    

Incorrect 

Posted by

divya.saini

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