Practice portal › Current Electricity › Wheatstone Bridge, Metre Bridge and Potentiometer

Resistance are connected in a meter bridge circuit as shown in the figure. The balancing length l₁ 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. [Figure: meter bridge wire AC with P=40 Ω in the left gap and Q in the right gap; galvanometer from the middle junction B to jockey J on the wire; l₁ measured from A; cell E and key K across the wire.]

Asked in JEE Main 26th July 1st Shift 2022 · Metre bridge

Figure: Metre bridge
Answer: 200

Step-by-step solution

First balance: P/Q=(40)/(60), so Q=3/2×40=60 Ω.

With x in series with P: (40+x)/(60)=(80)/(20)=4.

40+x=240, so x=200 Ω.

More Wheatstone Bridge, Metre Bridge and Potentiometer questionsAll Wheatstone Bridge, Metre Bridge and Potentiometer questions →

Reading this solution needs no sign-in. You only sign in to practise against the clock and keep your progress.

Practise this with a timer