The circular divisions of shown screw gauge are 50 . It moves 0.5 mm on main scale in one rotation. The diameter of the ball is

Question

The circular divisions of shown screw gauge are 50 . It moves 0.5 mm on main scale in one rotation. The diameter of the ball is (A) 2.25 mm (B) 2.20 mm (C) 1.20 mm (D) 1.25 mm

Tardigrade Admin · Accepted Answer

Since zero of the main scale coincides with the fifth division of the circular scale,
we have the zero error as

5 \times \frac{0.05}{50} = 0.05 mm

The actual measured (see the figure shown here) reading gives

(2 \times 0.5) mm + (25 \times \frac{0.5}{50}) mm - 0.05 mm

= (1 + 0.25 - 0.05) mm = 1.20 mm

Q. The circular divisions of shown screw gauge are 50 . It moves 0.5mm on main scale in one rotation. The diameter of the ball is

2.25 mm

2.20 mm

1.20 mm

1.25 mm

Since zero of the main scale coincides with the fifth division of the circular scale, we have the zero error as 5×500.05​=0.05mm The actual measured (see the figure shown here) reading gives (2×0.5)mm+(25×500.5​)mm−0.05mm =(1+0.25−0.05)mm=1.20mm

Q. The circular divisions of shown screw gauge are $50$ . It moves $0.5 mm$ on main scale in one rotation. The diameter of the ball is