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

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

1. Ameter scale
2. A vernier calliper where the 10 divisions in vernier scale matches with 9 divisions in main scale and main scale has 10 divisions in 1 cm
3. A screw gauge having 100 divisions in the circular scale and pitch as 1 mm
4. A screw gauge having 50 divisions in the circular scale and pitch as 1 mm

Answer: A vernier calliper where the 10 divisions in vernier scale matches with 9 divisions in main scale and main scale has 10 divisions in 1 cm