Question

A student measured the diameter of a small steel ball using a screw gauge of least count 0.001cm. The main scale reading is 5mm and zero of circular scale division coincides with 25 divisions above the reference level. If screw gauge has a zero error of – 0.004cm, the correct diameter of the ball is :- 

(1) 0.521cm 

(2) 0.525cm 

(3) 0.053cm 

(4) 0.529cm

Answer 1

Reading of screw gauge
= MSR + VSR × LC + zero error
= 0.5cm + 25 × 0.001cm + 0.004cm
= 0.529cm