When a detonator is exploded on a railway line, an observer standing on the rail 2 km away hears two sounds. What is the time interval between them? (Young's modulus of steel = 2 × 10¹¹Nm^-2, density of steel 8 × 10³ kg m^-3, density of air = 1.4 kgm^-3, ⲩ- for air = 1.4, atmospheric pressure = 10⁵Nm^-2)

Ans: 5.92 Sec

In a stormy day, a boy observes a lightning flash which is followed by a thunder 3 sec later. How would you estimate the distance of the lightning strike from the boy? (given velocity of sound on that day = 332m/s, velocity of light c = 3 x 10⁸m/s)

Ans: 996 m from him

A Source of sound of frequency 512 Hz emits waves of wavelength 64.5 cm in air at 20°C. What would be the velocity of sound at 0°C?

Ans: 318.77 m/sec

A source of sound produces a note of 512 Hz in air at 17°C with wavelength of 66.5 cm. Find the ratio of molar heat capacities at constant pressure to constant volume at NTP. Densities of air and mercury at NTP are 1.293 kg/m³ and 13600 kg/m³ respectively.

Ans: 1.36

Calculate the bulk modulus of a liquid in which longitudinal waves with frequency of 250 Hz have the wavelength of 8 m if the density of liquid is 900 kg m^-3

Ans: 3.6 × 10⁹ N/m²

In a resonance air column apparatus, the first and second resonance positions were observed at 18 cm and 56 cm respectively. The frequency of tuning fork used was 480 Hz. Calculate the velocity of sound in air and end correction of the tube.

Ans: 364.8 m/sec and 0.01 m

At what temperature, the velocity of sound in air is increased by 50% to that at 27°C?

Ans: 675 K

What is the difference between the speed of longitudinal waves in air at 27°C and at -13°C? What is the speed at 0°C?

Ans: 23.96m /sec, 331.1 m/sec

A source of sound of frequency 550Hz emits waves of wavelength 60 cm in air at 20°C. What would be the wavelength of sound from the source in air at 0°C?

Ans: 0.58 m

In a stormy day a person observes a lightning flash which is followed by thunder 3s later. How would you estimate the distance of the lightning striking from the person. [velocity of sound = 340 m/s, velocity of light = 3 × 10⁸ m/s]

Ans: 1020 m

At what temperature, the velocity of sound in air is increased by 60% to that at 27°C?

Ans: 495° C

Calculate the wavelength of wave in air at 25°C if the frequency of sound wave is 256 Hz and velocity of sound at 0°C is 330ms^-1.

Ans: 1.35 m