### 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.

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

N

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