(a) the ringing is not loud enough
   (b) the glass of the bell jar absorbs the sound waves
   (c) the bell jar is too small
   (d) there is no air or -any other gas in the bell jar
Ans: (d)
206. The speed of sound in a medium depends upon the properties of the
   medium such as
   (a) its density
   (b) its temperature
   (c) its elasticity
   (d) All the above
Ans: (d)
207. When we tighten the string of a sitar or tanpura its pitch
   (a) remains the same
   (b) increases
   (c) decreases
   (d) None of the above
Ans: (b)
208. The frequency of an ultrasonic wave is
   (a) the same as that of an audible sound
   (b) above the audible range
   (c) below the audible range
   (d) None of the above
Ans: (b)
209. The audible range of a normal human ear is frequencies ranging from
   (a) 10000 to 20000 Hz
   (b) 50 to 15000 Hz
   (c) 20 to 20000 Hz
   (d) 15 to 50000 Hz
Ans: (c)
210. The maximum displacement of the particle in a mechanical wave motion
   is known as
                                           90