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Olympiad Text Book VII-Physics (Vol-1) Narayana Group of Schools 1 MEMO GRAPH Quantities Physical Quantities Unit F.P.S Fundamental Quantities Supplementary Quantities Measurement of Physical Quantities P=nu System of units Traditional Systems FPS CGS MKS Modern System SI Dimensional Formula Dimensional equation Multiples and submultiples Practical units Conversion of units Derived Quantities C.G.S. M.K.S. S.I. System of units
VII-Physics (Vol-1) Olympiad Text Book Narayana Group of Schools 2 KNOW YOUR SCIENTISTS Albert Einstein (1879 –1955)born on 14 March 1879 in Germany, has an iconic status in modern Physics He is famous for his 'Theory of Relativity'. This theory showed that nothing can move faster than the speed of light. He changed our ideas of mass, energy, time and space. He proved that mass could the converted to energy. 'World Year of Physics' (WPY2005) is a United Nations' endorsed international celebration of Physics to coincide with 100th anniversary of the publication of Albert Einstein's 1905 Papers that revolutionized modern Physics. He received the Nobel Prize in Physics in the year 1921 for his discovery of the . Photoelectric effect is the phenomenon in which electrons are released from matter on absorption of light energy. law of photoelectric effect Michael Faraday (1791–1867) was one of the most influential scientists in the history of science. He was born in a poor family and at the age of 14, he started working in a book-binding shop. It is at this time that he read a lot of science books and developed and interest towards science. Later, he discovered electromagnetic induction and laws of electrolysis. He invented the electrical energy into mechanical energy using the concept of electromagnetism. He also discovered benzene, a very important chemical in use today.
Olympiad Text Book VII-Physics (Vol-1) Narayana Group of Schools 3 UNITS AND DIMENSIONS SYNOPSIS - 1 1. The study of nature and its laws is called physics. 2. Measurement should be made for knowing about the quantity of physical quan- tity. 3. The quantities which are measurable are called physical quantities. Ex : Length, mass, time, speed, etc. 4. To measure any physical quantity one standard is required i.e., called unit.Unit is a standard. Ex 1 : Metre is the standard by which we can measure length.  unit of length is metre Ex 2 : Second is the standard by which we can measure time.  unit of time is second 5. The number of times a standard quantity is present in a given physical quantity is called Numerical value of physical quantity. Physical quantity = Numerical value × Unit Ex : Let length of table = 3 metre Here 3 is the Numerical value and metre is the standard unit. Every physical quantity is expressed as number (N) followed by its unit (U). P = NU Where P is the measure of the quantity, N is the numerical value and U is unit of the quantity  Measure of the quantity (P) does not change with the choice of unit. P is constant  NU = constant P P NU N U      1 N SinceP iscons tant U     N U N U 1 1 2 2 (i.e., numerical value of a physical quantity is inversely proportional to unit chosen) Example: Height of a boy = 1.2 m = 120 cm In 1.2 m, unit is metre and numerical value is 1.2 In 120cm, unit is centimetre and numerical value is 120 6. Fundamental quantities : physical quantities which are independent of other physical quantities. Ex : Length, mass and time Fundamental units : Fundamental units are the units for measuring fundamen- tal quantities. These are independent of other units
VII-Physics (Vol-1) Olympiad Text Book Narayana Group of Schools 4 Ex: Unit of length - metre; Unit of mass - kilogram; Unit of time - second These are also called basic units. 7. Derived quantities : The physical quantities which depend on fundamental quan- tities. Ex : Area, volume and density etc. Derived units :Derived units are the units of derived physical quantities which are expressed in terms of fundamental units. Ex: The unit of speed is expressed by dividing the unit of distance by unit of time. Hence speed is a derived quantity and the unit of speed metre = second 8. The fundamental unit of length, mass and time taken together form a system of units. 9. There are four system of units. (i) British or F.P.S. system. (ii) French or C.G.S system. (iii) M.K.S system or metric system. (iv) International system or S.I. (kg) 10. S.I. system has seven basic units and two supplementary units. LAUGH & LEARN All the physicists are playing hide and seek. Einstein is in the ‘den’ and stands against the wall with his eyes closed and counts till 100 to enable all the physicists to run and hide. At the count of 100 Einstein turns around and finds Newton standing there. He screams, “Newton, you are out!” Newton says, “No, I ‘m not!” Einstein says, “Yes, you are. I can see you here in front of me”. Newton says, “I’m not out. Pascal is.” Einstein is a bit confused and starts to scratch his head and beard. Newton says “Here, Let me explain” He draws a square one meter by one meter on the floor and stands in the middle of it and says, “Newton per meter square is a Pascal, so it’s Pascal who’s out not me”