General Awareness-Physics Notes-Applied Physics & Basic Physics- Part 1

General Awareness - Online Physics Notes - Applied Physics and Basic Physics - Part I

  • Sound waves are longitudinal waves.
  • Sound waves cannot travel through vacuum.
  • Acoustic is the subject dealing with the study of sound.
  • Velocity of Sound is extreme in solid.
  • The velocity of sound in air increases with increase in temperature.
  • The velocity of sound in air is proportional to the square root of the absolute temperature.
  • The sound of high pitch: Shrill
  • The sound of low pitch: Sharp
  • Hertz is the unit of frequency.
  • Vibration of a string is a transverse motion.
  • Stethoscope is based upon the principle of multiple reflection.
  • Doppler effect describes the relationship between the pitch of sound and distance from the source of sound.
  • Doppler effect: Describes to find binary stars,
  • Sound signal is recorded as light signal on a cinema film.
  • When sound waves enter from air into water they bend away from the normal.
  • Light travels faster than sound.
  • Whispering gallery; Gol Gumbaz.
  • Uses of echoes: (1) Bats fly in the dark. (2) Detect the submarines under water.
  • Echo: We hear original and then reflected sound.
  • The obstacle should be at least 16.5 mts.
  • The time interval between sound production and its echo is 1/10 of a second.
  • Vibration of a string is transverse.
  • Microphones convert sound into electric energy.
  • Loud Speaker converts electric energy into mechanical energy and mechanical energy into sound energy.
  • A sound of single frequency is called tone.
  • Mach number: The ratio of the velocity of the body to the velocity of sound.
  • Expression for simple harmonic motion: a Sin (Wt-Kn).
  • The waves produced by the Sonometer is transverses stationary and polarized.
  • Lissajous figures are very useful in comparing frequencies.
  • The velocity of sound in gas is the square root of the adiabatic elasticity medium.
  • The velocity of sound in air decrease with increase in pressure.
  • The quality of tone depends upon the present.
  • The frequencies of two vibrating systems equal it is called resonance.
  • The velocity of sound in air is 332 meters/sec. 0 oC when the air is dry.
  • Ultra sonics are detected by the thermal detector.
  • Ultra sonic waves have frequencies higher than 20,000 Cycles per Sec.
  • Infra sonic waves have the frequencies less than 20hz,
  • A spherical liquid drop has a convex surface.
  • Surface Tension: Soap bubble.
  • The pressure inside a bubble is inversely proportional to its radius. 
  • Quincke's drop method is used for measuring surface tension and angle of contact for mercury in contact with glass. 
  • Cream separator: Centripetal force. 
  • Blotting paper: Capillary action.
  • Adhesion: Force of attraction between unlike molecules.
  • Cohension: Force of attraction between like molecules.
  • Rocket: Conservation of momentum.
  • Hygrometer: Instrument for measuring relative humidity.
  • Tensimeter: Device for measuring vapour pressure.
  • A falling in barometer: Storm.
  • Ballory are filled with hydrogen.
  • Sublimation: Vapourisation of a solid without first becoming a liquid.
  • In pressure cooker the water boils at more than 100o C.
  • Condensation: the change of vapour into liquid.
  • Heat from the sun reaches the earth by way of radiation.
  • Dry ice is solid carbondioxide.
  • Pyrometer is used for measuring higher temp.
  • When ice melts in a glass of water, the level of water in glass remains the same.
  • If a ship enters into sea from the lake the level of the ship rises.
  • S.I unit of heat is joule; in C.G.S system it is calorie.
  • Hope's experiment proves the density of water is maximum at 4°C.
  • The S.I unit of temperature is Kelvin.
  • Thermostat used to maintain a constant temperature.
  • Absolute zero: -273°C.
  • Absolute zero: -460°F
  • At -40° the Fahrenheit and Centigrade Scales are equal.
  • At 574.25°F the Fahrenheit and Kelvin are equal.
  • The temperature of human body is 36.9°C (fever:39°C).
  • Latent heat of fusion of ice=336 x 103 J/kg.
  • Regelation means refreezing.
  • Thermometric scales:  F = 9/5 C + 32 = 1.8C + 32,      C = (5/9 F-32) = 0.56 F-18
  • Laws of Reflection : (i) The angle of incidence is equal to the angle of reflection. (ii) The incident ray, reflected ray and normal to the surface lie in the same plane. 
  • Parallel Mirrors: (i) The No of images formed when an object is· kept in between two plane mirror is infinite, (ii) 3 images are formed when the two mirrors are inclained and the angle between the two mirror is 90° (5 images when 60°, 7 images when the angle is 45°, 11 images when the angle is 30°), (iii) The number of images formed (1) when the two mirros are inclained is equal to 1 = 360/1-1 is the angle between the mirrors, (iv) The number of images formed in Kaleidoscope is 5 (angle between the mirror is 60°). (v) Kaleidoscope and periscope are based on the principle of multiple reflection. 
  • Short Sight –Myopia : Eye ball too long, Focal length too small, Objects nearer are Clearly seen, Focus in front of retina, Rectified with Concave lens
  • Long Sight – Hyper Metropia : Eye ball too short, Focal length too long, Objects farer are Clearly seen, Focus behind the retina, Rectified with Convex lens
  • Infrared rays are discussed by William Herschell,
  • Wave length between 4X10-3 m and 7.5x 107m.
  • Headed zirconium and heated tungsten carbide emits infra-red.
  • Infrared: Used in the treatment of Thellmatic arthritis, Used in burglar alarms, Used in Photography (dew), The remote control (TV, VCR) sends commands in the form of infrared rays.
  • Ultra-violet rays are discovered by Ritter.
  • Wave length between 3900 X 10-lOm and 130.x 10-lOm.
  • Source-Sun and Moon: Used in Forensic science lab, Ultra-violet radiations helps for the preparation of vitamin D, Used in the treatment of bone diseases and tumors. Used for sterilizing the air in operation theatres and laboratories. 
  • Laser: Light amplification by stimulated emissions of Radiation. 
  • The laser light is coherent monochromatic and extremely intense.
  • The laser beam does not diverge.
  • Light is a form of Energy.
  • Light particles are known as photons.
  • Light waves are electromagnetic.
  • Velocity of the light: 3 x 108 m/sec.
  • Corpsclar theory of light: Sir Issac Newton.
  • Sky is blue due to Blue light is scattered the most by small particles of atmosphere.
  • Bats fly in the dark: Ultra sonics.
  • Velocity of liqht: Poucaulf's rotating mirror method.
  • Energy of photons: E=hr where 'h' is the Planck's constant (h =6.625 x 10-34 joules/sec)and r is the frequency of electromagnetic radiation. 
  • Rainbow: Dispersion.
  • If a green colour leaf is seen in red light it will appear as black.
  • Light travels fast in quarts.
  • If a disc which has the pure spectral colours painted on it in proper proportion is rotated rapidly, it produces, white light.
  • The distance between the projector and the screen, in a cinema theatre is increased by 1% the intensity of illumination is decreased by 2%.
  • Click for Part II
Posted by - Blog Author: 5:23 PM Last Updated at: 5:23 PM

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  1. How to download this materials

  2. cream separator is working on principal of centrifugal force not centripetal force.

  3. cream separator is working on the principal of centrifugal & not centripetal.