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Friday, 9 October

JEE Main 2021 · PhysicsNumerical answerNumerical valueMediumCalculation

JEE Main 25 July 2021, Shift 1, Physics Q29

Question 29 of 90 in this shift, Physics question 29 of 30, Section B.

Student A and Student B used two screw gauges of equal pitch and 100 equal circular divisions to measure the radius of a given wire. The actual value of the radius of the wire is 0.322 cm. The absolute value of the difference between the final circular scale readings observed by the students A and B is _________. [Figure shows position of reference 'O' when jaws of screw gauge are closed] Given pitch = 0.1 cm.

The figure, in words

Two screw gauge circular-scale diagrams with the reference line 'O' at top. Screw gauge (A): scale labelled 0, 5, 10 with the reference line at about 5 (zero error positive side). Screw gauge (B): scale labelled 90, 92, 95 with the reference line at about 92.

Official answer

13

NTA final key.

Chapter
Units and Measurements
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

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 42 of the 174 JEE Main shifts held from 2017 to 2026.