# Practical Physics

Topics: Density, Viscosity, Fundamental physics concepts Pages: 49 (6179 words) Published: March 7, 2014
DELTA UNIVERSITY FOR SCIENCE AND TECHNOLOGY
FACULTY OF PHARMACY

Practical Physics I
Fall 2012

[PRACTICAL PHYSICS I]

Contents

Fall 2012

(1) Fine Measurement Apparatuses --------------------------------------------------------------------------- 2 (2) Determination of the Mechanical Equivalent of Heat (Joule's Law) by Electrical Method 12 (3) Determination of the Melting Point of a Solid Material ------------------------------------------ 15 (4) Determination of the Specific Gravity using Archimedes Principle and Density Bottle --- 18 (5) Speed of Sound in Air -------------------------------------------------------------------------------------- 29 (6) The Simple Pendulum ------------------------------------------------------------------------------------- 31 (7) Specific Heat by the Method of Mixing --------------------------------------------------------------- 33 (8) Measurement of Viscosity of a Liquid by Stokes Law ---------------------------------------------- 37

Faculty of Pharmacy | Delta University

Page 1

(1) Fine Measurement Apparatuses
[PRACTICAL PHYSICS I]

Fall 2012

0. Objective

It is to measure the dimensions of a solid object using fine measuring instruments like:
1. Vernier caliper,
2. Micrometer Screw Gauge and
3. Spherometer Screw.

1. Vernier caliper
1.1. Apparatus

1. Vernier caliper, and
2. Parallelepiped solid object.
1.2. Theory

A very ingenious device for obtaining accuracy of a greater order than that obtainable by eye-estimation was invented by (Pierre Vernier), and is known by his name.

Faculty of Pharmacy | Delta University

Page 2

[PRACTICAL PHYSICS I]

Fall 2012

The vernier is a convenient attachment for determining accurately a fraction of the finest division on the main scale of a measuring instrument.

The simplest vernier scale has (10 divisions) that correspond in length to (9 divisions) on the main scale. Each vernier division is therefore shorter than a main scale division by ( 1 ) of a main scale division. The first vernier 10

division is ( 1 ) main-scale division short of a mark on the main scale, 10

the second division is (

2
) short of the next mark on the main scale, and
10

so on until the tenth vernier division is ( 10 ), or a whole division, short of a 10

mark on the main scale. It therefore, coincides with a mark on the main scale.
If the vernier scale is moved to the right until one mark, say the third, coincides with some mark of the main scale the number of tenths of a main-scale division that the vernier scale is moved is the number of the vernier division that coincides with any main-scale division. The third vernier division coincides with a main-scale mark, therefore the vernier scale has moved (3/10) of a main scale division to the right of its zero position. The vernier scale thus tells the fraction of a main-scale division that the zero of the vernier scale has moved beyond any main-scale mark.

Faculty of Pharmacy | Delta University

Page 3

[PRACTICAL PHYSICS I]

Fall 2012

The term "least count" is applied to the smallest value that can be read directly from a vernier scale. It is equal to the difference between a mainscale and a vernier division. Least account =

S
n

where (n) is the number of divisions on the vernier scale and (S) is the length of the smallest main-scale division.
In order to make a measurement with the instrument, first determine its least count, then read the number of divisions on the main scale before the zero of the vernier scale and note which vernier division coincides with a mark of the main scale. Multiply the number of the coinciding vernier mark by the least count to obtain the fractional part of a main-scale division to be added to the main-scale reading.

1.3. Method

1. Use the vernier caliper to measure the three dimensions of the parallelepiped body, the length (L cm), the width (W cm) and the depth (D cm).
2. Calculate the volume...