EX PERIME
ALM
spherical/cvlindrical body using vernier catlper
small
To measure the diameter of a
soARATUS
APPARATUS AND MATERIAL REQUIRED
body (a pendulum bob or a glass marble) or a small (iron/wooden
Vermier Callipers, a spherical
cylinder.
TÁEORY
1. Vernier constant = 1MSD - 1 VSD
division
Magnitude of the smallest main scale
Vernier constant = scale
Or Total number of divisions on the vernier
coinciding with some main scale division x C
2. Zero error, e=t No. of vernier division
3. Zero correction,
C=-Zero error =-e
4. Observed diameter,
D= MSR + VSR = N + nx VC
20
, Chapter2: VERNIER CALLIPERS
DIAGRAM
D
M
2 4 5 6 7 814 15
tasyluulu
P
A B (a) (b)
Glass marble
Fig. 2.9 (a) Measurement of diameter of a glass marble by using vernier callipers (b) Perpendicular diameter of qlass marble.
PROCEDURE
1. Examine the working of the vernier callipers. If the vernier scale is not sliding smoothly over the
main scale, apply machine oil/grease.
2. Determine the vernier constant of the vernier callipers. Record it stepwise in the observations.
3. Bring the movable jaws BDin close contact with the fixed jaws AC. Observe whether the zero of
vernier scale coincides with the zero of main scale. If this is not so, note the division on the vernier
scale that coincides with a division on the main scale. Record the zero error with a proper positive
correction. In
or negative sign. Repeat it three times and find the mean zero error and hence zero
Case there is n0 zero error, record as nil.
pressure
4. To measure the diameter of the small sphere/cylinder, hold it gently i.e., without any undue
in between the lower jaws A and B, as shown in Fig. 2.9. The jaws should be perfectly perpendicular
to the diameter aa' being measured. Gently tighten the screw S to clamp the jaws to the body.
Record the vernier
5. Note the main scale division N just to the left of the zero of the vernier scale.
counted from the zero
scale division n that coincides with some main scale division. This must be
end, of the vernier scale. Then, observed diameter aa' = N+nx VC.
6. Rotate the sphere/cylinder in its position through 90° so that diameter bb' is perpendicular to the
jaws. Proceeding as in step 5, note the main scale reading and the vernier scale reading and find the
observed diameter bb'.
two more
7. Measure the diameters aa' and bb' in two mutually perpendicular directions for atleast
positions of the sphere/cylinder.
Apply zero
8. Record all the observations in the tabular form. Find the mean observed diameter.
appropriate
correction to get the mean corrected diameter. Express the result in suitable units with
íumber of significant figures.
OBSERVATIONS AND CALCULATIONS
A. For vernier constant
1 main scale division (MSD) =1 mm =0.1 cm
10 VSD=9MSD
1VSD = MSD
10
9 1 1
Vernier constant = 1MSD -1 VSD =1 MSD MSD : MSD = x1mm
10 10 10
=0.1 mm =0.01 cm
21
ALM
spherical/cvlindrical body using vernier catlper
small
To measure the diameter of a
soARATUS
APPARATUS AND MATERIAL REQUIRED
body (a pendulum bob or a glass marble) or a small (iron/wooden
Vermier Callipers, a spherical
cylinder.
TÁEORY
1. Vernier constant = 1MSD - 1 VSD
division
Magnitude of the smallest main scale
Vernier constant = scale
Or Total number of divisions on the vernier
coinciding with some main scale division x C
2. Zero error, e=t No. of vernier division
3. Zero correction,
C=-Zero error =-e
4. Observed diameter,
D= MSR + VSR = N + nx VC
20
, Chapter2: VERNIER CALLIPERS
DIAGRAM
D
M
2 4 5 6 7 814 15
tasyluulu
P
A B (a) (b)
Glass marble
Fig. 2.9 (a) Measurement of diameter of a glass marble by using vernier callipers (b) Perpendicular diameter of qlass marble.
PROCEDURE
1. Examine the working of the vernier callipers. If the vernier scale is not sliding smoothly over the
main scale, apply machine oil/grease.
2. Determine the vernier constant of the vernier callipers. Record it stepwise in the observations.
3. Bring the movable jaws BDin close contact with the fixed jaws AC. Observe whether the zero of
vernier scale coincides with the zero of main scale. If this is not so, note the division on the vernier
scale that coincides with a division on the main scale. Record the zero error with a proper positive
correction. In
or negative sign. Repeat it three times and find the mean zero error and hence zero
Case there is n0 zero error, record as nil.
pressure
4. To measure the diameter of the small sphere/cylinder, hold it gently i.e., without any undue
in between the lower jaws A and B, as shown in Fig. 2.9. The jaws should be perfectly perpendicular
to the diameter aa' being measured. Gently tighten the screw S to clamp the jaws to the body.
Record the vernier
5. Note the main scale division N just to the left of the zero of the vernier scale.
counted from the zero
scale division n that coincides with some main scale division. This must be
end, of the vernier scale. Then, observed diameter aa' = N+nx VC.
6. Rotate the sphere/cylinder in its position through 90° so that diameter bb' is perpendicular to the
jaws. Proceeding as in step 5, note the main scale reading and the vernier scale reading and find the
observed diameter bb'.
two more
7. Measure the diameters aa' and bb' in two mutually perpendicular directions for atleast
positions of the sphere/cylinder.
Apply zero
8. Record all the observations in the tabular form. Find the mean observed diameter.
appropriate
correction to get the mean corrected diameter. Express the result in suitable units with
íumber of significant figures.
OBSERVATIONS AND CALCULATIONS
A. For vernier constant
1 main scale division (MSD) =1 mm =0.1 cm
10 VSD=9MSD
1VSD = MSD
10
9 1 1
Vernier constant = 1MSD -1 VSD =1 MSD MSD : MSD = x1mm
10 10 10
=0.1 mm =0.01 cm
21
