Flash of lightning reaches earlier than the sound of thunder. Why?

$(i)$ Which property of sound wave determines:
$(a)$ loudness
$(b)$ pitch?
$(ii)$ $A$ $SONAR$ station picks up a return signal after $3 \ s$. How far away is the object? (Speed of sound in water is $1440 \ m \ s^{-1}$)
$(iii)$ How can reverberations in a big hall or auditorium be reduced?

$A$ person fires a gun in front of a building $167 \ m$ away. If the speed of sound is $334 \ m \ s^{-1}$,calculate the time in which he hears an echo. (in $s$)

Define the following terms and state their $SI$ units:
$(a)$ Wavelength $(b)$ Time period $(c)$ Amplitude.
Establish the relation $V = v \lambda$,where the symbols have their usual meanings.

Given that sound travels in air at $340 \, m s^{-1}$,find the wavelength of the waves in air produced by a $20 \, Hz$ sound source. If the same source is put in a water tank,what would be the wavelength of the sound waves in water? (Given,speed of the sound in water $= 1480 \, m s^{-1}$)

$A$ body vibrating with a time period of $5 \times 10^{-3} \text{ s}$ produces a wave travelling in a medium with a velocity of $1450 \text{ m s}^{-1}$. Calculate its wavelength and the frequency of vibration of the body.