E N D
PRACTICAL SKILL WORKING AS A PHYSICIST
Objectives: • To study the of a basic a resolution of a apparatus • To determine how to read a VERNIER CALIPER.
PARTS OF A VERNIER CALIPER 1 - Outside jaws: used to take external measures of objects 2 - Inside jaws: used to take internal measures of objects 3 - Depth probe: used to measure the depth of objects 4 - Main scale (cm & inch) 5 - Vernier Scale 6 - Retainer: used to block movable part
Measuring Using the Vernier: • Keep the body to be measured between the fixed jaw and mobile jaw • Without pressure on it. • Take the main scale reading. • The division of the vernier that coincides with any division on the main scale is • also noted. This is the vernier scale reading. • Then, the measurement of the object will be • = Main scale reading + (vernier scale reading x least count) • Here, • Least count = Value of One Main Scale Division / Total Number of Divisions • on the Vernier Scale • The units of measurement is in millimeters (mm).
Measuring Instruments • Vernier Caliper • A vernier caliper has a zero error if the `0' mark on the main scale is not in line with the '0' mark on the vernier scale when the jaws of the caliper are fully closed
Electronic vernier calipers are also available The procedure for taking measurements remains the same.
Measuring Instruments • Vernier Caliper • (a) Positive zero error • Zero error = +0.04 cm.
Measuring Instruments • Vernier Caliper (b) Negative zero error • Zero error = -0.02 cm.
For vernier caliper: Total reading = MSR + (VSR x LC) MSR = Main Scale Reading VSR = Vernier Scale Reading LC = Least Count MSR = 2.7cm x 10 = 27mm VSR = 1(5) = 5 x 0.02 mm = 0.1mm Total Reading = 27.1 mm
MSR = .9 cm x 10 = 9 mm VSR =3.6(5) = 18 x 0.02 mm = .36 mm Total Reading = 9.36 mm
MSR = ______________________________ VSR = ______________________________ Total Reading = _______________________
SCREW GAUGE/ MICRO METER Micrometer: Is a tool designed to measure the thickness of an object
MEASURING USING THE MICROMETER: • 1. Keep the object between the measuring jaws. • 2. Bring the measuring jaws together by turning • the screw until the object is clamped and the • thickness to be read no longer changes. • 3. Take the main reading and the head scale • reading.
For micrometer: Total reading = MSR + (HSR x LC) MSR = Main Scale Reading HSR = Head Scale Reading LC = Least Count QUESTION 1 MSR = 7 mm HSR = 0 x 0.01 mm = 0 mm Total Reading = 7 mm
QUESTION 2 MSR = 8 mm HSR = 12 x 0.01 mm = 0.12 mm Total Reading = 8.12 mm
QUESTION 3 MSR = __________________________ HSR = __________________________ Total Reading = ___________________
Electronic screw gauge is also available. The procedure for taking the measurements remains the same
Conclusion: • The diameter of the metal ball is _____________ • The length of the cube is ____________. • The diameter of the wire is ____________.