Concept and nature of sound.Wave length and frequency, infrasonic and Ultrasonic sounds, Sources of Infrasonic sound In nature, Ultrasonic sound characteristics and some applications.

Sound is a longitudinal wave, in which the particles oscillate to and fro in the same direction of wave propagation. Sound waves cannot be transmitted through vacuum. The transmission of sound requires at least a medium, which can be solid, liquid, or gas. Newton to derive a relation for the velocity of sound in a gaseous … Read more

System of Units: MKS, CGS and SI

Measurement of any physical quantity involves comparison with a certain basic, arbitrarily chosen, internationally accepted reference standard called unit. The result of a measurement of a physical quantity is expressed by a number (or numerical measure) accompanied by a unit. A unit of measurement is a definite magnitude of a quantity, defined and adopted by … Read more