Q. Which of the following is true for the calibration of instruments? (Solved)
1. in casting and fabrication shops the measurements made are of more precise nature as compared to those made in machine shop and tool room
2. periodical calibration is made for optical measuring instruments
3. there is no need of periodic calibration in universal microscope
4. preventive maintenance is not necessary for optical measuring instruments
- b. periodical calibration is made for optical measuring instruments