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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedHardCalculation

JEE Main 17 March 2021, Shift 2, Physics Q16

Question 16 of 90 in this shift, Physics question 16 of 30, Section A.

The four arms of a Wheatstone bridge have resistances as shown in the figure. A galvanometer of 15 Ω\Omega resistance is connected across BD. Calculate the current through the galvanometer when a potential difference of 10 V is maintained across AC.

The figure, in words

Wheatstone bridge drawn as a diamond with corners A (left), B (top), C (right), D (bottom): AB = 100 ohm, BC = 10 ohm, AD = 60 ohm, DC = 5 ohm; a galvanometer G (circle with an arrow) connects B and D vertically; a 10 V cell is connected between A and C through an external wire loop below the bridge.
  1. (1)2.44 μA2.44\ \mu\mathrm{A}
  2. (2)2.44 mA2.44\ \mathrm{mA}
  3. (3)4.87 μA4.87\ \mu\mathrm{A}
  4. (4)4.87 mA4.87\ \mathrm{mA}Official answer

Official answer

Option 4

NTA final key.

Chapter
Current Electricity
Topic
Wheatstone Bridge
Idea tested
Unbalanced Bridge Analysis

Same idea in other shifts

Asked 4× in all
  1. 15 Apr 2023, Shift 1 · Q60A network of four resistances is connected to 9 V battery, as shown in figure. The magnitude of voltage difference between the points A…MediumNumerical valueHas a figure
  2. 9 Jan 2020, Shift 1 · Q20In the given circuit diagram, a wire is joining points B and D. The current in this wire is :MediumDiagram basedHas a figure
  3. 4 Sep 2020, Shift 2 · Q23Four resistances 40 Ω\Omega, 60 Ω\Omega, 90 Ω\Omega and 110 Ω\Omega make the arms of a quadrilateral ABCD. Across AC is a battery of…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.