A resistance is to be measured using a meter bridge; the student chooses the standard resistance R to be 100 . The student finds the null point at l₁=16 cm. To get the null point near the middle of the wire, the value of R will be

Step-by-step solution

For a meter bridge, the balance condition is given by X R = l 100 - l , where X is the unknown resistance and R is the standard resistance. Given R = 100 and l = 16 cm, we can find X : X 100 = 16 100 - 16 = 16 84 X = 1600 84 = 400 21 19.04 To obtain the null point near the middle of the wire, the balancing length should be l' 50 cm. Using the balance condition again with the new standard resistance R' : X R' = 50 100 - 50 = 1 R' = X 19.04 Thus, the value of the standard resistance should be chosen as 19 . Answer: 1