In what manner temperature affects the speed of sound?

  1. An infant can easily recognise her father’s voice. Name the characteristics of sound involved.
  2. In what manner temperature affects the speed of sound?
  3. Define ultrasonic wave. How is it possible that bats are able to fly at night without colliding with other objects?
  4. Write one important condition required to hear an echo.
  1. Quality is the characteristic of sound due to which distinction can be done between two sounds.
  2. Speed of sound increases with the increase in temperature.
  3. The sound of frequency higher than 20000 Hz is called ultrasonic wave. Bats emits high frequency ultrasonic squeak while flying and listen to echoes produced by reflection of their squeak from the obstacles prey or object in their path. From the time taken by the echo to be heard, bats can determine the distance of the object by changing the direction without colliding with it.
  4. The condition to hear an echo is that the minimum distance between the obstacle and source of sound be atleast 17.2 m.