The vernier caliper

VERNIER CALIPER
WORKING
LEAST COUNT
READING
ZERO ERROR
CORRECTION
QUIZ

1. 1 THE VERNIER CALIPER INSIGHTS OF PHYSICS

2. THE VERNIER CALIPER The Vernier Caliper is a precision instrument that can be used to measure internal and external distances extremely accurately.  The accuracy obtained in measurements using a meter rule is up to 1 mm. However an accuracy greater than 1 mm can be obtained by using it. A Vernier Calipers consists of two jaws. One is a fixed jaw with main scale attached to it. Main scale has centimeter and millimeter marks on it. The other jaw is a moveable jaw. It has Vernier scale having 10 divisions over it such that each of its division is 0.9 mm. Unit 1: Physical Quantities and Measurement -Vernier Caliper 2 INSIGHTS OF PHYSICS

3. Figure: THE VERNIER CALIPER Unit 1: Physical Quantities and Measurement - Vernier Caliper 3 INSIGHTS OF PHYSICS

4. Least Count Of Vernier Caliper The difference between one small division on main scale division and one Vernier scale division is 0.1 mm. It is called least count (LC) of the Vernier Calipers. Least count of the Vernier Calipers can also be found as given below: 4 Unit 1: Physical Quantities and Measurement - Vernier Caliper INSIGHTS OF PHYSICS

5. Working of a Vernier Calipers 5 Unit 1: Physical Quantities and Measurement - Vernier Caliper The sliding jaw runs on the main scale with the guiding surface, which is accompanied by a Vernier scale, in which it has a measuring tip on the left side. When two measuring tip surfaces are in contact with each other, the scale shows zero reading. The finer adjustment of the movable jaw can be done by adjusting screw. First, the whole movable jaw assembly is adjusted so that the two measuring tips just touch the part to be measured. Then lockout B is tightened. INSIGHTS OF PHYSICS

6. 6 Unit 1: Physical Quantities and Measurement - Vernier Caliper Final adjustment depending upon the sense of correct feeling is made by adjusting screw, which makes the part containing locking nut A and sliding jaw to move, as the adjusting screw rotates on a screw which is in a way fixed to the movable jaw. After all, the final adjustment has been done, the locking nut has also been tightened and the reading has been noted. Measuring tips are designed so that they can be used to measure external dimensions as well as internal dimensions. Working of a Vernier Calipers INSIGHTS OF PHYSICS

7. Zero Error and Zero Correction 7 Unit 1: Physical Quantities and Measurement - Vernier Caliper First of all find the error, if any, in the measuring instrument. It is called the zero error of the instrument. Knowing the zero error, necessary correction can be made to find the correct measurement. Such a correction is called zero correction of the instrument. Zero correction is the negative of zero error. INSIGHTS OF PHYSICS

8. Zero Error and Zero Correction To find the zero error, close the jaws of Vernier Calipers gently. If zero line of the Vernier scale coincides with the zero of the main scale then the zero error is zero (figure a). 8 Unit 1: Physical Quantities and Measurement - Vernier Caliper INSIGHTS OF PHYSICS

9. Zero error will exist if zero line of the Vernier scale is not coinciding with the zero of main scale (figure b). 9 Unit 1: Physical Quantities and Measurement - Vernier Caliper Zero Error and Zero Correction INSIGHTS OF PHYSICS

10. Zero error will be positive if zero line of Vernier scale is on the right side of the zero of the main scale and will be negative if zero line of Vernier scale is on the left side of zero of the main scale (figure c). 10 Unit 1: Physical Quantities and Measurement - Vernier Caliper Zero Error and Zero Correction INSIGHTS OF PHYSICS

11. Taking a Reading on Vernier Calipers Let us find the diameter of material using Vernier Callipers. Place the material between jaws of the Vernier Callipers. Close the jaws till they press the opposite sides of the object gently. Note the complete divisions of main scale past the Vernier scale zero in a tabular form. Next find the Vernier scale division that is coinciding with any division on the main scale. 11 Unit 1: Physical Quantities and Measurement - Vernier Caliper INSIGHTS OF PHYSICS

12. Taking a Reading on Vernier Calipers Multiply it by least count of Vernier Callipers and add it in the main scale reading. This is the diameter of material. Add zero correction (Z.C) to get correct measurement. Repeat the above procedure and record observations. 12 Unit 1: Physical Quantities and Measurement - Vernier Caliper INSIGHTS OF PHYSICS

13. Advantages and Disadvantages of Vernier Scales Advantages Accuracy and Precision Integrated Scales Versatility Durability Cost Disadvantages Good Eyesight is Required Knowledge of Vernier Calipers is Required Possibility of Errors More Accurate Tools Available 13 Unit 1: Physical Quantities and Measurement - Vernier Caliper INSIGHTS OF PHYSICS

14. QUICK QUIZ What is the least count of the Vernier Callipers? The least count of the Vernier caliper is 0.1mm or 0.01cm . What is the range of the Vernier Callipers used in your Physics laboratory? The range of the Vernier calipers used in physics laboratory is 12cm. How many divisions are there on its Vernier scale? Vernier scale have 10 divisions over it such that each of its division is 0.9 mm. Why do we use zero correction? Zero correction is used to get accurate and precise measurements. 14 Unit 1: Physical Quantities and Measurement - Vernier Caliper INSIGHTS OF PHYSICS

15. INSIGHTS OF PHYSICS Thank you Physical Quantities and Measurement UNIT 1