Question

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

SI.No.	R(\Omega|)	$l\left(cm\right)$
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)

$4$

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