ExamBro
ExamBro
TS EAMCET · Physics · Current Electricity

In a meter bridge a \(30 \Omega\) resistance is connected in the left gap and a pair of resistances \(P\) and \(Q\) in the right gap. Measured from the left, the balance point is \(37.5 \mathrm{~cm}\), when \(P\) and \(Q\) are in series and \(71.4 \mathrm{~cm}\) they are in parallel. The values of \(P\) and \(Q\) (in \(\Omega\) ) are

  1. A 40 10
  2. B 35 15
  3. C 30 20
  4. D 25 25
Verified Solution

Answer & Solution

Correct Answer

(C) 30 20

Step-by-step Solution

Detailed explanation

Ist case \(\begin{aligned} & \frac{30}{P+Q}=\frac{l}{(100-l)} \\ & \frac{30}{P+Q}=\frac{37.5}{(100-37.5)} \\ & \frac{30}{P+Q}=\frac{37.5}{62.5} \\ & P+Q=\frac{30 \times 62.5}{37.5} \end{aligned}\) \(P+Q=50\)....(i) IInd case…