Need for Pressure Wave

Q. If we want to increase the intensity of a sound wave by 9 times, then

1. Pressure amplitude must increase to 3 times
2. Displacement amplitude must increase to 3 times
3. Frequency amplitude must increase to 3 times
4. Displacement amplitude must increase by 3 times and frequency must increase by 2 times

Q. Decibel is the unit used to measure which characteristic of sound?

1. pitch
2. loudness
3. quality
4. frequency

Q. Two sound waves move in the same diretion in the same medium. The pressure amplitudes of the waves are equal but the wavelength of the first wave is double the second. Let the average power transmitted across a cross saection by the first wave be $P_1$ and that by the second wave be $P_2$ . Then

1. $P_1=P_2$
2. $P_1=4P_2$
3. $P_2=2P_1$
4. $P_2=4P_1$

Q. As a result of a distant explosion, an observer first senses a ground tremour, then hears the explosion. What accounts for this time lag?

Q. Two sound waves of equal intensity I produce beats . The maximum intensity of sound produced in beats will be

1. I
   
2. 4I
3. 2I
4. I/2

Q. The frequency of sound can remain unchanged even if we double the length of the wire, provided:

1. Tension of the wire is doubled
2. Tension of the wire is decreased four-fold
3. Tension of the wire is halved
4. Tension of the wire is increased four-fold

Q. Two sound wave have equal displacement amplitudes, but one has twice the frequency of the other.
Which has the greater pressure amplitude and by what factors is it greater?

Q. The maximum pressure amplitude and maximum displacement amplitude are equal for a sound wave in water

1. True
2. False