3. Sound
(i) Reflection of Sound Waves; echoes: their use; simple numerical problems on echoes.
Production of echoes, condition for formation of echoes; simple numerical problems; use of echoes by bats, dolphins, fishermen, medical field. SONAR.
(ii) Natural vibrations, Damped vibrations, Forced vibrations and Resonance - a special case of forced vibrations.
Meaning and simple applications of natural, damped, forced vibrations and resonance.
(iii) Loudness, pitch and quality of sound:
Characteristics of sound: loudness and intensity; subjective and objective nature of these properties; sound level in decibel(dB) (as unit only); noise pollution; interdependence of: pitch and frequency; quality and waveforms (with examples).