Home
Class 12
PHYSICS
In a meter bridge circuit, resistance, i...

In a meter bridge circuit, resistance, in the left hand gap is `2Omega` and an unknown resistance X is in the right hand gap as shown in figure below. The null point is found to be 40 cm from the left end of the wire. What resistance should be connected to X so that the new null point is 50 cm from the left end of the wire ?

Text Solution

Verified by Experts

By Wheatstone bridge principle :
`P/Q=R/S`
Case I : When I = 40 cm
`implies l/(100-l)=2/X`
`implies (40)/(100-40)=2/X`
`implies 40/60 =2/X`
`implies 2X = 6`
`:. X = 6/2 = 3Omega`
Case II: When l. = 50 cm
`P/Q=R/S`
`implies (l.)/(100-l.)=2/(X.)`
`= (50)/(100-50) =2/(X.)`
`:. X.=2Omega`
`:. X.ltX`
So resistance need to be decreased and a new resistor should be connected in parallel.
`:. ` A resistance `X_1` must be connected in parallel to X.
`:. 1/(X.)=1/X+1/X_1`
`implies 1/2=1/3+1/X_1`
or `1/X_1=1/2-1/3`
`= (3-2)/6=1/6`
`implies X_1 = 6 Omega`
`:. 6 Omega` resistance must be connected in parallel to X to have new null point at 50 cm.
Promotional Banner

Similar Questions

Explore conceptually related problems

In a metre bridge when the resistance in the left gap is 2Omega and an unknown resistance in the right gap, the balance point is obtained at 40 cm from the zero end. On shunting the unknown resistance with 2Omega find the shift of the balance point on the bridge wire.

Circuit diagram of metre bridge is shown in figure. The null point is found at a distance of 40cm from A. it now a resistance of 12Omega is connected in parallel with S, the null point occurs at 64cm.

In a meter bridge, the null point is found at a distance of 40 cm from A. If a resistance of 12 Omega in connected in parallel with S the null point occurs at 50.0 cm from A Determine the value of R and S

In a meter bridge, the null point is found at a distance of 40 cm from A. If now a resistance of 12 Omega is connected in parallel with S, the null point occurs at 60 cm from A. Determine the value of R.

In a metre bridge the null point is found at a distance of 35 cm from A. If now a resistance of 10Omega is connected in parallel with S, the null point occurs at 50 cm. Determine the values of R and S.

Two unkonwn resistances X and Y are connected to left and right gaps of a meter bridge and the balancing point is obtained at 80cm from left. When a 10 Omega resistance is connected parallel to X, the balancing point is 50cm from left. The values of X and Y respectively are

In a meter-bridge experiment with a resistance R_(1) in left gap and a resistance X in a right gap. null point is obtained at 40 cm from the left emf. With a resistance R_(2) in the left gap, the null point is obtainned at 50 cm from left hand. Find the position of the left gap is containing R_(1) and R_(2) (i) in series and (ii) in parallel.

In a meter bridge, the null points is found at a distance of 33.7 cm from A. If now a resistance of 12 Omega is connected in parallel with S, the null point occurs at 51.9 cm. Determine the values of R and S.

Two unknown resistances are connected in two gaps of a meter-bridge. The null point is obtained at 40 cm from left end. A 30Omega resistance is connected in series with the smaller of the two resistances, the null point shifts by 20 cm to the right end. The value of smaller resistance in Omega is

In a meter bridge experiment the ratio of left gap resistance to right gap resistance is 2:3 the balance point from is