Question

In a meter bridge experiment, the circuit diagram and the corresponding observation table are shown in figure

SI NO	R $(\Omega )$	l(cm)
1.	1000	60
2.	100	13
3.	10	1.5
4.	1	1.0

Which of the readings is inconsistent ?

• A. 4
• B. 1
• C. 2
• D. 3

Answer 1

Answer: (A)

as $x=\frac{R\left(100-\ell \right)}{\ell }$
for (1) $x=\frac{1000\times \left(100-60\right)}{40}\approx 667$
for (2) $x=\frac{100\times \left(100-13\right)}{13}\approx 669$
for (3) $x=\frac{10\times \left(100-1.5\right)}{98.5}\approx 656$
for (4) $x=\frac{1\times \left(100-1\right)}{1}\approx 95$
So option (4) is completely different hence correct Ans. (4)