Question 665: Current Electricity

Question

Three resistances, P, Q, R each of 2$\Omega $ and an unknown resistance S from the four arms of a Wheatstone bridge circuit. When a resistance of 6 $\Omega $ is connected in parallel to S the bridge gets balanced. What is the value of S?

Accepted Answer

A balanced wheatstone bridge simply requires
${P \over Q} = {R \over S} \Rightarrow {2 \over 2} = {2 \over S}$
Therefore, S should be 2$\Omega $.
A resistance of 6$\Omega $ is connected in parallel.
In parallel combination,
${1 \over R} = {1 \over {{R_1}}} + {1 \over {{R_2}}}$
${1 \over 2} = {1 \over 6} + {1 \over S}$
$ \Rightarrow S = 3\Omega $

Answer

3 $\Omega $

Answer

6 $\Omega $

Answer

1 $\Omega $

Answer

2 $\Omega $.

Current Electricity

Three resistances, P, Q, R each of 2\Omega and an unknown resistance S from the four arms of a Wheatstone bridge circuit. When a resistance of 6 \Omega is connected in parallel to S the bridge gets balanced. What is the value of S?

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