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

Question

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 ? (A) 50 cm (B) 80 cm (C) 40 cm (D) 70 cm

Tardigrade Admin · Accepted Answer

We have from meter bridge experiment, (R1/R2) = (ℓ1/ℓ2), where ℓ2 = (100-ℓ1)cm In the first case, X/Y = 20/80 In the second case (4X/Y) = (ℓ/100-ℓ) ℓ = 50 cm.

Q. In a metre bridge experiment null point is obtained at 20cm 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 ?

50 cm

80 cm

40 cm

70 cm

We have from meter bridge experiment, R2​R1​​=ℓ2​ℓ1​​, where ℓ2​=(100−ℓ1​)cm In the first case, X/Y=20/80 In the second case Y4X​=100−ℓℓ​ ℓ=50cm.

We have from meter bridge experiment,
$\frac{R _{1}}{R _{2}} = \frac{ℓ _{1}}{ℓ _{2}}$ , where $ℓ_{2} = (100 - ℓ_{1}) c m$
In the first case, $X / Y = 20/80$
In the second case $\frac{4 X}{Y} = \frac{ℓ}{100 - ℓ}$
$ℓ = 50 c m .$