Q.61)-What is the unit of frequency?
  • Decibel
  • Watt
  • Hertz
  • Newton
Q.62)-Sounds of frequencies below 20 Hz are called
  • Infrasonic sound
  • Ultrasonic sound
  • Intrasonic sound
  • Reflected sound
Q.63)-What is the minimum distance(in meters) required to hear an echo?
  • 10
  • 13
  • 17
  • 21
Q.64)-Which among the following determines the pitch of a sound?
  • Amplitude
  • Frequency
  • Loudness
  • Wavelength
Q.65)-What is the SI unit of frequency?
  • Newton
  • Watt
  • Farad
  • Hertz
Q.66)-Who pioneered diagnostic ultrasound?
  • Alexander fleming
  • Ian Donald
  • A.Laveran
  • Robert Koch
Q.67)-What is the SI unit of intensity of sound?
  • Decibel
  • Newton
  • Heartz
  • Tesla