GENERAL PHYSICS

• Thermal radiation - electromagnetic radiation as a result of thermal motion of molecules.
• Light- also produced during electrical discharges through ionized gases.
• Speed of light in vacuum- c = 3 x 108m/s
• Ray- imaginary line to describe the directions in which light propagates
• Specular reflection - reflection at a definite angle from a very smooth surface
• Diffuse reflection - scattered reflection from a rough surface
• Nb>Na - A tay entering a usterial of farger index of refraction bends and the normal.
• Nb<Na -A ray entering a nuterial of smaller indes of refraction bends way from the normal.
• Normal incident - ray oriented along the normal dees not hent, regardless of the materials.
• intensities of the reflected and refracted rays depend on the angle of incidence, the two indexes of refraction, and the polarization (that is, the direction of the electric-field vector) of the incident ray
• frequency of the wave does not change when passing from one material to another.
• wavelength of the wave is different in general in different materials.
• v = λf -Unit of Wave speed is the distance a wave travels in a given amount of time
• Polarization - characteristic of all transverse waves
• Unpolarized light (natural light)- light is a random mixture of waves linearly polarized in all possible transverse directions.
• light bulbs - example of Unpolarized light
• Incident Ray -the ray of light that falls on the reflecting surface.
• Reflecting Ray-the ray of light that is sent back by the reflecting surface
• Normal -a line at right angle to the reflecting surface to the point of incidence
• Angle of Incidence - the angle made by the incident ray and the normal.
• Angle of Reflection - it is the angle made by the reflected ray and the normal.
• Object - it is the thing that forms an image on the screen.
• Image - it is the reflection of the object on the screen.
• Virtual Image -the image that cannot be obtained on a screen (a surface where image is formed)
• Real Image -the image that is formed directly on the screen
• angle of incidence is equal to the angle of reflection
• Incident ray - reflected ray and the normal to the mirror at the point of incidence all lie on the same plane
• incident ray and reflected ray - it lie on either side of the normal
• The image formed in a plane mirror is • Virtual and Erect • Same size as of the Object • Same distance from the mirror as the object is in front of it • Literally Inverted.
• Concave Mirror -It is a spherical mirror that has its reflecting surface curved inwards
• Convex Mirror - it is a spherical mirror that has its reflecting surface curved outwards
• Focus of a Concave Mirror - a point on the principal axis, where all the rays parallel to the principal axis converge
• Focus of Convex Mirror - It is a point on the principal axis where the reflected rays appear to converge
• Focal Length of Spherical Mirror - distance between the pole and the principal focus
• Radius of Curvature - is two times the Focal Length of any Spherical Mirror
• Uses of Concave Mirrors - Shaving mirrors, Torches, search lights, and vehicle headlights, Used by dentists to get large images of patient's teeth and In solar furnaces to concentrate heat
• Uses of Convex Mirrors - Vehicles as rear-view mirrors to see traffic at the rear-side and Used as a device to check thefts in shops
• Optimal focus -center point of lens
• Principal axis -line passing to the optical center
• Focus -the point where ray converge after refraction of lens