Ncert Exercises & Solutions

A resistance R is to be measured using a meter bridge. A student chooses the standard resistance S to be 100 $Ω$ . He finds the null point at l₁= 2.9 cm. He is told to attempt to improve accuracy. Which of the following is a useful way?

1.	He should measure l₁ more accurately
2.	He should change S to 1000 Ω and repeat the experiment
3.	He should change S to 3 Ω and repeat the experiment
4.	He should give up hope of more accurate measurement with a meter bridge

Step 1:

The percentage error in R can be minimized by adjusting the balance point near the middle of the bridge, ie., when $I_{1}$ is close to 50 cm. This requires a suitable choice of S.

$Since, \frac{R}{S} = \frac{l_{1}}{(100 - l_{1})} = \frac{l_{1}}{100 - l_{1}}$

Step 2:

Since here, R: S=2.9: 97.1 implies that the S is nearly 33 times that of R. In order to

make this ratio 1:1, it is necessary to reduce the value of S nearly 1/33 times i.e., nearly 3 $Ω$ .

NEET Information

courses

Company

Botany Questions

Chemistry Questions

Physics Questions

Zoology Questions