Physics 6

ഭൗതികശാസ്ത്രത്തിലേക്ക് തിരികെ വരുമ്പോൾ ശബ്ദവുമായി ബന്ധപ്പെട്ട ചോദ്യങ്ങളാണ് ഇന്നത്തെ പാഠത്തിൽ

• Study of Sound

                Acoustics

• Sound waves cant travel through

                Vacuum

• Sound waves are 

                Longitudinal

• Sound travels faster in

                Solids

• Sound travels slower in

                Gases

• Solid medium in which speed of Sound is maximum

                Steel

• Hearing capacity of human

                20 to 20,000 Hz

• Speed of Sound in air

                340 m\s

• Speed of Sound in water

                1453 m\s

• As the density of medium increases, speed of Sound

                Increases

• As the temperature of medium increases, speed of Sound

                Increases

• Properties of Sound

                Pitch, Loudness, Timbre (Quality)

• Shrillness of Sound is known as

                Pitch

• Intensity of Sound is identified as 

                Loudness

• Unit of frequency of Sound

                Hertz (Hz)

• Unit of Intensity of Sound

                Decibel (db)

• Unit of Sound Pollution

                Decibel

• Normal unit of measuring Pollution

                Parts per million (ppm)

• Normal Sound level

                60-120 db

• Intensity of human sound

                60-65 db

• Sound level causing damage to human ears

                Above120 db

• Sound allowed in hospital areas at night

                About 40 db

• Sound allowed in residential areas

                50 db in day 40 db at night

• Organ in human beings which helps to produce Sound

                Larynx

• Sound is produced due to

                Vibration

• Phenomenon of sound to obstructed by a hard surface and send back to source is called

                Reflection of Sound

• Echo and Reverberation are due to

                Reflection of sound

• A vibrating system or external force drives another system to oscilate with greater amplitude at a specific freaquency is known as

                Resonance

• Persistence of sound as a result of multiple reflection is known as

                Reverberation

• Phenomenon of hearing a sound reflection after hearing the original sound is 

                Echo

• Minimum sound required for the production of Echo

                17 Meter

• Phenomenon of sound which used in Stethoscope

                Reflection of sound

• Phenomenon of sound which used in SONAR

                Echolocation

• Sound waves used in SONAR

                Ultrasonic Sound

• SONAR stands for

                Echolocation

• Devices used to measure the depth of the sea

                Echo Sounder (SONAR), Fathometer

• Unit of measuring the depth of the sea

                Fathom (1 Fathom= 6 Feet=1.82 metre)

• Devices used to get the picture of the objects at the bottom of the sea

                SONAR

• Whistle used for calling dogs

                Galton whistle

• Devices used in the studies of sound

                Sonometer

• Device used for recording sound under water

                Hydrophone

• Term used to denote the speed lower than the speed of sound

                Subsonic

• Term used to denote 2 times the speed of sound

                Supersonic

• Term used to denote 5 times the speed of sound

                Hypersonic

• Sound waves produced by Elephants and Whales for communication

                Infrasonic

• Sound waves produced by Bats and Dolphin

                Ultrasonic

• Sound waves used in Ultrasound scanning

                Ultrasonic

• Sound lower than 20 Hz

                Infrasonic

• Sound higher than 20,000 Hz

                Ultrasonic
                                                                                (To be Continued...)