JEE Main202623 January 2026Morning ShiftPhysicsExperimental PhysicsActual
In a screw gauge, the zero of the circular scale lies 3 divisions above the horizontal pitch line when their metallic studs are brought in contact. Using this instrument thickness of a sheet is measured. If pitch scale reading is 1 mm and the circular scale reading is 51 then the correct thickness of the sheet is _ _ _ _ mm. [Assume least count is 0.01 mm ]
Options
- A1.50
- B1.48
- C1.54
- D1.51
Correct answer
C. 1.54
Step-by-step solution
For a screw gauge, the measurement formula is: Reading = Pitch scale + (Circular scale × Least count) - Zero error The zero of circular scale lies 3 divisions above the pitch line, indicating negative zero error: Zero error = -3 × 0.01 = -0.03 mm Reading = 1 + (51 × 0.01) - (-0.03) = 1 + 0.51 + 0.03 = 1.54 mm