Aim:- To measure internal diameter and depth of a given
beaker using Vernier calipers and hence
find it’s Volume.
Apparatus:- Vernier calipers, a beaker and a magnifying
glass.
Theory:-
For measuring internal diameter and depth:
If with the body between the jaws, the zero
of Vernier scale lies ahead of Nth division of main scale, then main
scale reading (M.S.R.) = N.
If nth division of Vernier scale coincides
with any division of main scale,
then Vernier scale reading (V.S.R) = n x
(L.C.) (L.C. is least count of Vernier callipers)
= n x (V.C.) (V.C. is Vernier constant of Vernier callipers)
Total reading, T.R = M.S.R + V.S.R (L.C. =
V.C.)
=N+ n x (V.C)
For Volume:
Volume of beaker = internal area of cross
section x depth
Or V = π(D/2)2.d
Where, D = Internal diameter of beaker
d = Depth of beaker
Observation:-
Known mass of the block (m) = ……. g.
Determination of Vernier Constant (Least
Count) of the Vernier Callipers
1 M.S.D = 1mm
1O V.S.D = 9 M.S.D
Therefore, 1 V.S.D = M.S.D = 0.9 mm.
Vernier Constant, V.C = 1 M.S.D - 1 V.S.D =
(1 — 0.9) mm = 0.1 mm = 0.01 cm.
Zero error (i) ...... cm, (ii)..... cm, (iii)
...... cm.
Mean zero error (e) = ...... cm.
Mean zero correction (c) = - e = ...... cm.
Table for the Internal Diameter (D):-
Serial Number
|
Main Scale
Reading
|
Vernier Scale
Reading
|
Total Reading
|
||
No. of Vernier
division coinciding(n)
|
Value [n x (V.C)]
|
Observed [Do
= N + n x (V.C)]
|
Corrected (D = Do + C)
|
||
1
|
|
|
|
|
D1
|
2
|
|
|
|
|
D2
|
3
|
|
|
|
|
D3
|
4
|
|
|
|
|
D4
|
5
|
|
|
|
|
D5
|
6
|
|
|
|
|
D6
|
![]() |
Internal diameter of beaker |
Table for the Depth (d):-
Serial Number
|
Main Scale
Reading
|
Vernier Scale Reading
|
Total Reading
|
||
No. of Vernier
division coinciding(n)
|
Value [n x (V.C)]
|
Observed [do
= N + n x (V.C)]
|
Corrected (d = do + C)
|
||
1
|
|
|
|
|
d1
|
2
|
|
|
|
|
d2
|
3
|
|
|
|
|
d3
|
4
|
|
|
|
|
d4
|
5
|
|
|
|
|
d5
|
6
|
|
|
|
|
d6
|
Calculations:-
Mean corrected internal diameter: D = D1 + D2
+ D3 + D4 + D5 + D6 / 6
Mean corrected depth: d = d1 + d2 + d3
+ d4 + d5 + d6 / 6
Volume of the beaker = π(D/2)2.d
Result:-
The volume of the beaker is ……… cm3.
Precautions:-
- Motion of Vernier scale on main scale should be made smooth (by oiling if necessary).
- Vernier constant and zero error should be carefully found and properly recorded.
- The body should be gripped between the jaws firmly but gently (without undue pressure on it from the jaws).
- Observations should be taken at right angles at one place and taken at least as three different places.
Sources of Error:-
- The Vernier scale may be loose on main scale.
- The jaws may not be at right angles to the main scale.
- The graduations on scale may not be correct and clear.
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