225. Sound waves In "air travel faster if
   (a) frequency is higher
   (b) wavelength is smaller
   (c) pitch is smaller
   (d) air is warmer
Ans: (d)
226. The acoustical quality of a room depends on
   (a) the size and shape of the room
   (b) the ability of the ceiling, walls and floor to exclude unwanted sound
   (c) the use of furnishings made of sound absorbing materials
   (d) All the above
Ans: (d)
227. Ultrasonic waves are used –
   (a) in medical and surgical diagnosis
   (b) in testing the quality of the linings and pads used in vehicles and aircraft
   (c) to clean surgical instruments, jewellery and similar articles
   (d) All the above
Ans: (d)
228. SONAR (Sound Navigation Ranging) is
   (a) used by warships and military aircraft to locate enemy submarines
   (b) used by ships to determine the depth of water beneath them
   (c) a detective device that uses sound to locate under - water objects
   (d) All the above
Ans: (d)
229. A device used in a ship for the purpose of measuring the depth of the sea
   (a) an altimeter
   (b) a fathometer
   (c) a hydrometer
   (d) a sonometer
Ans: (b)