Sound Waves

Velocity (v) of sound in air, by vibrating resonating column is found by ______ ($${\ell}_1$$, $${\ell}_2$$ and n are first second resonating lengths and frequency of tuning fork used respectively).
Ultrasound waves have :
A cars horn produced a sound wave of a constant frequency. Car is moving to the right as shown above. The five points A, B, C, D and E are marked, at which point would a man listen a lower pitch than pitch produced when car is at rest?
The velocity of sound in a gas in which two waves of wavelengths $$50$$ cm and $$50.5$$ cm produces $$6$$ beats per second is?
A supersonic jet produces waves in air. The wave front is