Learn

Saturday, 31 October

JEE Main 2022 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 26 July 2022, Shift 1, Physics Q56

Question 56 of 90 in this shift, Physics question 26 of 30, Section B.

Resistances are connected in a meter bridge circuit as shown in the figure. The balancing length l1l_1 is 40 cm. Now an unknown resistance xx 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 xx will be __________ Ω\Omega.

The figure, in words

Meter bridge: a horizontal wire from A (left) to C (right), with a jockey at point J marked on it; the length from A to J is marked l1. Above the wire are two gaps containing boxes labelled P (marked P = 4 ohm) on the left and Q on the right, joined at a point B; a galvanometer G connects B to J. Below the wire a cell E and a key K are connected between A and C.

Official answer

20

NTA final key.

Chapter
Current Electricity
Topic
Wheatstone Bridge
Idea tested
Meter Bridge Principles

Same idea in other shifts

Asked 7× in all
  1. 1 Feb 2024, Shift 2 · Q50In a metre-bridge when a resistance in the left gap is 2 Ω2\,\Omega and unknown resistance in the right gap, the balance length is found to…MediumSingle correct
  2. 31 Jan 2024, Shift 2 · Q49The resistance per centimeter of a meter bridge wire is rr, with X ΩX\ \Omega resistance in left gap. Balancing length from left end is at…MediumSingle correct
  3. 27 Jul 2022, Shift 1 · Q51In a meter bridge experiment, for measuring unknown resistance 'S', the null point is obtained at a distance 30 cm from the left side as…EasyNumerical valueHas a figure
  4. 27 Jul 2022, Shift 2 · Q52In the given figure of meter bridge experiment, the balancing length AC corresponding to null deflection of the galvanometer is 40 cm. The…MediumNumerical valueHas a figure
  5. 18 Mar 2021, Shift 2 · Q26Consider a 72 cm long wire AB as shown in the figure. The galvanometer jockey is placed at P on AB at a distance xx cm from A. The…EasyNumerical valueHas a figure
  6. 9 Jan 2020, Shift 2 · Q23In a meter bridge experiment S is a standard resistance. R is a resistance wire. It is found that balancing length is l=25l = 25 cm. If R is…EasyNumerical valueHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.