In a meter bridge, the null point is found at a distance of 25 cm from A. If now a resistance of 10 Ω is connected in parallel with S, the null point occurs at mid point of AB. The value of R is :-

Question

In a meter bridge, the null point is found at a distance of 25 cm from A. If now a resistance of 10 Ω is connected in parallel with S, the null point occurs at mid point of AB. The value of R is :- (A) 6.67 Ω (B) 1.67 Ω (C) 2.67 Ω (D) 4.67 Ω

Tardigrade Admin · Accepted Answer

Case-1 ( S / R )=(75/25) or ((100-ℓ/ℓ)) ( S × 10/( S +10) R )=(50/50) ( S / R )=3 S =3 R ldots(1) Case-2 S × 10=( S +10) R 3 R × 10=(3 R +10) R 30=3 R +10 3 R =20 R =(20/3)=6.67 ohm

Q. In a meter bridge, the null point is found at a distance of $25 c m$ from $A$ . If now a resistance of $10 Ω$ is connected in parallel with $S$ , the null point occurs at mid point of $A B$ . The value of $R$ is :-

$6.67 Ω$

$1.67 Ω$

$2.67 Ω$

$4.67 Ω$

Case-1
$\frac{S}{R} = \frac{75}{25}$ or $(\frac{100 - ℓ}{ℓ})$
$\frac{S \times 10}{( S + 10 ) R} = \frac{50}{50}$
$\frac{S}{R} = 3$
$S = 3 R \dots (1)$
Case-2
$S \times 10 = (S + 10) R$
$3 R \times 10 = (3 R + 10) R$
$30 = 3 R + 10$
$3 R = 20$
$R = \frac{20}{3} = 6.67 o hm$

Q. In a meter bridge, the null point is found at a distance of 25cm from A. If now a resistance of 10Ω is connected in parallel with S, the null point occurs at mid point of AB. The value of R is :-

6.67Ω

1.67Ω

2.67Ω

4.67Ω