A car is driven at 30m/s between two sources, each producing sound waves of 1.50x10^6 Hz. The sound heard by driver rises and fades as he travels from one sound source to the other. Find the period of regular fading.
No relevant equations provided.
The Attempt at a Solution
Since the sound rise and fades along the line connecting the two sources, I believe a standing wave has been formed, where the two end points are open ends. I figure that in one second, the car moves 30m and the waves make 1.50x10^6 cycles, so the wavelength (which is the distance covered in one cycle) must equal 2x10^-5 m (or λ=v/f). Since fading takes place at every node, that is λ/2, distance between adjacent nodes = 0.00001 m. how do I translate
that into time interval between successive nodes? The answer given is 3.3 seconds.