Basic notes for Physics NTS test

What is physics?

Physics The branch of science which deals with the study of properties of matter, energy and their mutual relationship is called Physics.

Describe  main branches of Physics

Main branches of physics are; (1) Mechanics The branch of physics that deals with the study of

(1) Mechanics The branch of physics that deals with the study of motion of material objects under the action of forces.

(2) Heat and Thermodynamics The branch of physics which deals with the transformation of heat energy into other forms of energy. (3) Optics The branch of physics which deals with the nature of light, its propagation, reflection, refraction, dispersion and the wave properties of light. (4) Electricity and magnetism It deals with the study of static as well as moving charges and the phenomena that

(3) Optics The branch of physics which deals with the nature of light, its propagation, reflection, refraction, dispersion and the wave properties of light. (4) Electricity and magnetism It deals with the study of static as well as moving charges and the phenomena that

(4) Electricity and magnetism It deals with the study of static as well as moving charges and the phenomena that occurs due to the effects of charges. (5) Atomic physics The branch of physics which deals with the structure and properties of individual atoms.

(5) Atomic physics The branch of physics which deals with the structure and properties of individual atoms.

What is physical quantity? Describe its types.

Physical quantity :

A quantity which can be easily observed and measured is called Physical quantity.

For example Distance, mass, time, Area, Volume, etc.

There are two types of Physical Quantities;

(1) Base physical quantities

Those physical Quantities which are the simplest standards selected by the scientists for other quantities are called base or standard physical quantities.

For examples Length, mass, time, electric current, temperature, etc.

(2) Derived physical quantities

Those physical quantities which are obtained by multiplying or dividing the Base Physical Quantities are called derived physical quantities.

For examples Force, Area, Volume, speed, acceleration etc.

What is international system of units?

The set of units used for the physical quantities are called system of units. The system of units in which the unit of length, mass and time is meter, kilogram and second respectively is called system international (SI). It is based on seven basic units from which all other units are derived.

What are prefixes? Explain

Prefixes In scientific calculation some time we have to deal with quantities that are either very large or small compared with the base units, in such cases we use higher or smaller units of the standard unit. These smaller or higher units are in power of 10 which are called prefixes. For examples The distance between two cities is taken in kilometer rather than in meter. The thickness of a wire is taken in millimeter rather than in meter.

What is meant by significant figures? How it can be identified.

Significant figures It can be defined as “The number of accurately known figures and the first doubtful figure are known as significant figures. For example 9.8 , 9.7 , 9.94 , 9.85 have two significant figures

Give points to advocate that physics is linked with Biology, Chemistry, Geography and Astronomy?

Physics is the root of every science. Its major developments are in Chemistry, Biology, Geology, Agriculture, Environmental science, Astronomy, Engineering and in Medicine. It also laid the foundation of modern science. Physics approves our quality of life by providing new instruments for medical applications such as computer tomography (CT scan), magnetic resonance imaging (MRI), ultrasonic imaging and laser surgery.

Vernier calipers

An instrument used to measure small length up to 0.1 mm ( 0.01 cm). It was invented by a French mathematician Pierre Vernier in 1631.

Construction It consists of two Scale i.e. main scale and Vernier scale.

(1) Main scale It has marking of 1mm each and contains a jaw on its left end.

(2) Vernier scale A sliding scale that has marking of 0.9 mm each. It has total 10 or 20 divisions. Vernier scale also contains a jaw on its left end.

What is zero error in Vernier calipers?

If the jaws of the Vernier calipers are closed and the zero of the main scale does not coincide with the zero of the Vernier scale, then there is an error in the Vernier calipers which are called zero error.

There are two types of zero errors

(1) Positive zero error When the zero of the Vernier scale remains right to the zero of the main scale, the error is called positive zero error. The positive zero error must be subtracted from each reading.

(2) Negative zero error When the zero of the Vernier scale remains left to the zero of the main scale, the error is called negative zero error. The negative zero error must be added with each reading.

Screw gauge

A micrometer screw gauge is used to measure small lengths or diameter up to 0.01 mm or 0.001 cm.

Measuring cylinder

The device use to measure the volume of a substance using a liquid is called measuring cylinder. It is made up from a transparent plastic or glass having a vertical scale in millimeter (ml) or in cubic centimeter (cm3 ). When a liquid is poured into the cylinder, the volume is read from the scale on the side. The surface of the liquid curves upward at the point where it touches the inside of the cylinder. This curvature is called the meniscus. To read the volume of a liquid accurately the base of the measuring cylinder must be placed on a flat surface and eye must be leveled with the bottom of the meniscus.

Give some examples of applications of work done by physists.

Work done by some common physists are as under.

Alberuni determined the circumference of the earth.

Bu Ali Sena introduce the laws of reflection of light.

Bu Ali Sena introduce the laws of reflection of light.

Yaqub kindi express musical nodes in terms of scientific method.

 Dr. Abdussalam proposed the grand unification theory in physics.

Name the convenient unit you will use to measure a. Width of a book b. length of a room c. diameter of a wire

The most convenient unit of (a) Width of a book is centimeter. (b)

(a) Width of a book is centimeter. (b)

(b) Length of a room is meter. (c) Diameter of a wire is millimeter

(c) Diameter of a wire is millimeter

Base physical quantities

Temperature, Time, Length

Derived physical quantities

Volume, Area, Density