A student measured the length of a rod and wrote it as 3.50 cm. Which instrument did he use to measure it?

A student measured the length of a rod and wrote it as 3.50 cm. Which

1.	A student measured the length of a rod and wrote it as 3.50 cm. Which instrument did he use to measure it?
Answer» A screw gauge having 100 divisions in the circular scale and pitch as 1 mm. A screw gauge having 50 divisions in the circular scale and pitch as 1 mm. A METER scale. A vernier calliper where the 10 divisions in vemier scale matches with 9 division in main scale and main scale has 10 division in 1 cm. Solution :Measured LENGTH of a rod is 3.50cm, hence least count of instrument used near should be 0.01cm = 0.1mm. Least count = 1MSD - IVSD ... (1). In vemier scale IMSD = IMM and 9MSD = 10VSD `:.` IVSD=0.9 MSD `:.` From equation (i) Least count of vernier calliper `=1MSD=0.9MSD` `=0.1 MSD =0.1 mm, 0.01 cm`