What is the Units and Dimensions of Physics in Easy words

Units and Dimensions:-

Resonance (MRI). Ultrasound Scanning, X-ray, ECG. used in the treatment of cancer, Radioactive tracers used in of or cancerous tumours are examples of use of physics in Physics made compulsory subject in all the diploma courses in engineering because Of the Medicine, applications of physics ill every branch of engineering. For example in Civil Engineering, it to better understand banking of roads, racing tracks. bending of a cyclist, earthquake and resistant echoes reverberation for better sound effects in buildings, hydraulics In Electrical Engineering, what is AC and DC frequency, phase difference, electromagnetism electric power plants, working of motors. transmission of electricity, effect of temperature on the transmission of electricity etc.

In Mechanical Engineering, thermodynamic physics principles are very essential to such diverse areas such as refrigeration, chemical engineering, internal combustion engines, heat transfer, Heat transfer is what also drives the weather and understanding the heat balance of the earth in its critical stage and tells us about what should be done about global warming .
In computer. IT and ECE physics not only helps to know about the nature and properties Of different materials used in the related industry, but also optical-fiber communication, laser, microwave , communication, waves, different materials used in storage devices and much more.

Measurement : Lord Kelvin once said, • " When you can measure what you are speaking about. and express it in numbers. you have advanced to the stage of science, but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind. "
It is a long way to the sun. It is a long way to U.S.A. It is a long way to Delhi. May be, but in these cases the distances are measured in millions, thousands and hundreds of kilometers . respectively. Similarly time is often described with equal lack of precision. As, "There will be solar eclipse soon". 'The building will be completed soon'. 'Dinner will be ready soon'. In each case, we have to guess from the context whether soon refers to years, weeks, or minutes. Sometimes, the context is not helpful. For example, the assurance, 'I will be ready soon' is ambiguous, In this case, the speaker is probably concerned more with appeasement than with measurement.
Qualitative description must be replaced by quantitative measurement. Measurement is a counting process. Physics deals with accurate measurement, yet the degree of accuracy aimed at depends on the purpose for which the measurements are being made. There is no such thing as absolute accuracy. No physical measurement is absolutely correct. Since measurement is most important in physics so in this unit, we will study about different physical quantities, their units, accurate measurement and if any error occurs then how to measure and minimize the effect of that error. We will also study how to convert a physical quantity from one system of units into another system Of units.

1.1. PHYSICAL QUANTITIES :-

All quantities in terms of which laws of physics can be expressed and which can be measured directly or indirectly are called physical quantities. In other words. a quantity which can be measured is called a physical quantity. e.g, mass. length, time, velocity, speed. area, etc.

Physical quantities are of two types :-
(i) Fundamental quantities
(ii) Derived quantities