4.0 g of a gas occupies 22.4 litres at NTP. The specific heat capacity of the gas at constant volume is 5.0 J K^$$-$$1 mol^$$-$$1. If the speed of sound in this gas at NTP is 952 m s^$$-$$1, then the heat capacity at constant pressure is
(Take gas constant R $$=$$ 8.3 J K^$$-$$1 mol^$$-$$1)

A string is stretched between fixed points separated by 75.0 cm. It is observed to have resonant frequencies of 420 Hz and 315 Hz. There are no other resonant frequencies between these two. The lowest resonant frequency for this string is

The number of possible natural oscillations of air column in a pipe closed at one end length 85 cm whose frequencies lie below 1250 Hz are (Velocity of sound = 340 m s^$$-$$1)

A speeding motorcyclist sees traffic jam ahead him. He slows down to 36 km hour^$$-$$1. He finds that traffic has eased and a car moving ahead of him at 18 km hour^$$-$$1 is honking at a frequency of 1392 Hz. If the speed of sound is 343 m s^$$-$$1, the frequency of the honk as heard by him will be