JEE Main202226 Jul 2022Morning ShiftPhysicsCurrent ElectricityActual
Resistance are connected in a meter bridge circuit as shown in the figure. The balancing length l 1 is 40   cm . Now an unknown resistance x is connected in series with P and new balancing length is found to be 80   cm measured from the same end. Then the value of x will be _____ Ω .
Correct answer
0
Step-by-step solution
Applying balanced condition for meter bridge Initially, P Q = 40   cm 60   cm = 2 3               . . . 1 Finally, P + x Q = 80   cm 20   cm = 4 1             . . . 2 Dividing equation 2 by ( 1 , P + x P = 4 × 3 2 = 6 ⇒ 1 + x P = 6 ⇒ x P = 5 ∴    x = 5 P = 5 × 4 = 20   Ω