05-01-2018, 04:35 PM
*Persistence of sound as a result of multiple reflection
Ans : Reverberation
*The phenomenon of hearing a sound by reflection from a surface or obstacle after hearing the original sound
Ans : Echo
*Phenomenon of sound 'which is used in stethoscope
Ans : Reflection of sound
*Minimum distance required for the production of Echo
Ans : 17 meters
*Phenomenon of sound which is applied in SONAR
Ans : Echolocation
*Sound waves used in SONAR
Ans : Ultrasonic Sound
*SONAR - Sound Navigation and Ranging *Sound phenomenon which helps Bats to detect prey and obstacles in their path in night
Ans : Echolocation
*Devices used to measure the depth of the sea
Ans : Echo Sounder (SONAR), Fathometer
*Unit of measuring the depth of the sea-
Ans : Fathom
* 1 Fathom = 6 feet = 1.82 metre Device used to get the picture of the objects at the bottom of the sea
Ans : SONAR
Intensity of sound
*Threshold of hearing - 0 db
*Breathing - 10 db
*whispering - 20 db
*Ticking clock - 30 db
*Polite Alarm clock - 30 - 40 db
*Television,Alarm clock - 75db
*Vacuum cleaner - 80 db
*Traffic noise - 60 - 120 db
*Aircraft noise - 90 - 120 db
*Thunder storm - 110 db
*Shot gun - 120 db
*Rocket taking off - 130 db
*Jet take off - 140 db
*Space Vechicle launched - 140 -170 db
*Above 125 db cause damage to hearing.
*Normal sound level in decibel is 60 - 120 db
*About 40 db is allowed in hospital areas at night
waves & Rays
*Waves used in point to point fixed telecommunication
Ans : Microwaves
*Waves used in Radio and Television broadcasting
Ans : Radio Waves
*Electro magnetic wave which is having lowest frequency
Ans : Radio Waves
*Electro magnetic waves having highest wavelength
Ans : Radio Waves
*Rays which cause sunburn
Ans : UltravioletRays
*Electromagnetic rays used for detecting the adulterations in ghee
Ans : Ultraviolet Rays
*Rays used for identifying the counterfeit currency
Ans : Ultraviolet Rays
*Light rays in tube light
Ans : Ultraviolet Rays
*Rays used in TV remotes
Ans : Infrared
*Rays used in distant photography
Ans : Infrared
*The heat of the sunlight is due to
Ans : Infrared rays
