Current Electricity - Result Question 102

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

(a) 3Ω

(b) 6Ω

(c) 1Ω

(d) 2Ω

[2007]

Show Answer

Answer:

Correct Answer: 107. (a)

Solution:

  1. (a) A balanced wheatstone bridge simply requires

PQ=RS22=2S

Therefore, S should be 2Ω.

A resistance of 6Ω is connected in parallel.

In parallel combination,

1R=1R1+1R2

12=16+1SS=3Ω

If the resistance is connected in parallel to the right gap resistor in the metre bridge, then balancing length increases and hence jockey moves towards right.



NCERT Chapter Video Solution

Dual Pane