When the gap is closed without placing any object in the screw gauge whose least count is 0.005 mm, the 5th division on its circular scale coincides with the reference line on main scale, and when a small sphere is placed reading on main scale advances by 4 divisions, whereas circular scale reading advances to five times to the corresponding reading when no object was placed. There are 200 divisions on the circular scale. The radius of the sphere is
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Question

When the gap is closed without placing any object in the screw gauge whose least count is 0.005 mm, the 5th division on its circular scale coincides with the reference line on main scale, and when a small sphere is placed reading on main scale advances by 4 divisions, whereas circular scale reading advances to five times to the corresponding reading when no object was placed. There are 200 divisions on the circular scale. The radius of the sphere is

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G1 Physics · Accepted Answer

LC=0.005 mm. At closure the 5th division gives +0.025 mm zero error. With the sphere, main-scale advance is 4 divisions; the circular reading becomes 25 divisions. Corrected diameter is 4.10 mm, so radius is 2.05 mm. Correct answer: D.