phy-1.md

Aim of the Experiment

To measure the diameter of a small cylinder using Vernier callipers.

APPARATUS REQUIRED

Vernier callipers, small cylinder

Theory

1. Vernier constant = 1 MSD - 1 VSD
2. Zero error, e = $\pm$ No. of vernier division coinciding with some main scale division $\text{X}$ Vernier constant
3. Zero correction,
   • $c$ = - zero error = $-e$
4. Observed diameter,
   • D = MSR + VSR = N + n * VC

Observation and Calculation

VC = 1 - $\frac{9}{10}$
=> 0.01 mm

$D_1$

$D_1R_1$ = 3.1 + (0.01 * 2)
=> 3.12 cm

$D_1R_2$ = 3.1 + (0.01 * 4)
=> 3.14 cm

$\underbar{D}_1$

Result

The diameter of the given cylinder is $\underbar{3.131 cm}$

Precautions

1. Vernier scale should slide smoothly over the main scale. Apply machine oil or grease of required.
2. The vernier constant and zero error should be carefully determined and recorded.
3. The body should be gripped gently between the jaws without and undue pressure.
4. Each observation should be recorded with correct significant figures and units.

Sources of Error

1. The jaws of the vernier callipers may not be perpendicular to the main scale.
2. The vernier scale may be loose.
3. The zero error of the instrument may not have been taken into account.
4. Personal errors due to parallax and improper recording.