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← JEE Main 2022 · 29 Jul · Shift 1
PhysicsSingle correct+4 / -1Question 50 of 90

JEE Main 2022 · 29 Jul · Shift 1, Physics question 50

In an experiment to find out the diameter of wire using screw gauge, the following observations were noted :

(A) Screw moves 0.5 mm on main scale in one complete rotation

(B) Total divisions on circular scale = 50

(C) Main scale reading is 2.5 mm

(D) 45th^{\text{th}} division of circular scale is in the pitch line

(E) Instrument has 0.03 mm negative error

Then the diameter of wire is :

A screw gauge: U-frame with anvil P and spindle Q gripping the wire, sleeve with main scale and thimble showing division 45 on the reference line.
Choose one option
Answer and worked solution

Official answer: C

Least count 0.550=0.01\frac{0.5}{50}=0.01 mm. Reading 2.5+45×0.01=2.952.5+45\times0.01=2.95 mm.

Negative error of 0.03 mm is added back: 2.98 mm.

(C)