Question

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

(a) 3Ω 

(b) 6 Ω 

(c) 1 Ω

(d) 2 Ω

Answer 1

Correct option  (a) 3Ω 

Explanation:

For a balanced Wheatstone bridge, we get

Therefore, the equivalent circuit diagram drawn below.