Notes:
The following laws are dealt with in the classical physics: 1. Law of conservation of energy 2. Law of conservation of angular momentum 3. Law of conservation of linear momentum 4. Law of conservation of charge

Notes:
X-rays were discovered by Wilhelm Conrad Roentgen. W.C Roengten discovered X-Rays while actually working on Cathode rays. X-rays is a form of electromagnetic radiation having a wavelength ranging from 0.01 to 10 nanometers and frequencies in the range 30 petahertz to 30 exahertz. Some Uses of X-Rays: The main use of X-rays is in medicine to check for a broken bone inside body. X-rays can also be used to kill cancer cells. X-rays are used at security checks at airports, railway stations etc. to check customers and baggage. X-rays are also used art historians to see if a picture has been painted on top of an older one. X-ray diffraction is also very important in spectroscopy and as a basis for X-ray crystallography.

Notes:
The range of masses involved in the study of Physics ranges from 10^-30 kg to 10⁵⁵ kg. 10^-30kg is the mass of an electron and 10⁵⁵ kg is the mass of known observable universe. The range of time scale involved in the study of Physics ranges from 10^-22 s to 10¹⁸ s. The range of length involved in the study of Physics ranges from 10^-14m to 10²⁶ m.

Notes:
Edwin Hubble, an american astronomer, and was the first to prove that the universe is expanding. According to Expanding Universe theory, the universe is presently expanding. Hubble proved that there is a direct relationship between the speeds of distant galaxies and their distances from Earth. This is now known as Hubble’s Law.

Notes:
J.J Thompson was the first scientist to discover and identify the electrons and to make the discovery of the first subatomic particle. He was also the first scientist to find evidence for isotopes of a stable (non-radioactive) element in 1913, as part of his exploration into the composition of canal rays (positive ions). His experiments to determine the nature of positively charged particles led to the development of the mass spectrograph. J.J Thompson belonged to United Kingdom. He won the Nobel Prize in Physics in 1906 for his work on the conduction of electricity in gases.

Notes:
bar, torr and Pascal are the units used for measuring pressure whereas shake is a unit of time. 1 bar = 10⁵ Pa 1 bar = 760 torr 1 bar = 1 atmospheric pressure Shake is the smallest practical unit of time. 1 shake = 10^-8s

Notes:
Sedrial day is the time taken by the earth to complete one rotation about its axis w.r.t a fixed star Solar day is the time taken by the earth to complete one rotation about its axis w.r.t the sun. Shake is the smallest practical unit of time 1 shake = 10^-8s Tropical year: The year in which there is a total solar eclipse

Notes:
Steradian is the unit of Solid Angle (Angle in Space). One steradian is defined as the solid angle of a sphere subtended at the centre of a sphere by that surface of the surface whose area is equal to the square of the sphere’s radius. Its symbol is sr.

Notes:
The physical quantities which have both magnitude and direction are called as Vector quantities. Some examples of Vector quantities: Acceleration, Velocity, Torque, Displacement, Gravitational Intensity, Force.