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In a metre bridge experiment null point is obtained at 20 cm from one end of the wire when resistance X  is balanced against another resistance  Y .If X<Y  , then where will be the new position of the null point from the same end, if one decides to balance a resistance of  4X against Y ?

  • Option 1)

    50 cm

  • Option 2)

    80 cm

  • Option 3)

    40 cm

  • Option 4)

    70 cm


Answers (2)

As we learnt in

Wheat stone Bridge -

It is an arrangement of four resistances which can be used to measure one of them in terms of rest

- wherein



In first case, \frac{x}{y}=\frac{20}{100-20}=\frac{20}{80}=\frac{1}{4}

In second case, \frac{4x}{y}=\frac{l}{100-l}=\frac{4}{4}=\frac{l}{100-l}

l = 50 cm

Option 1)

50 cm

This option is correct.

Option 2)

80 cm

This option is incorrect.

Option 3)

40 cm

This option is incorrect.

Option 4)

70 cm

This option is incorrect.

Posted by

Sabhrant Ambastha

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