Question1
Two speakers, one directly behind other, are each generating a 268-Hz sound wave. What is the least separation distance between speakers that will produce destructive interference at a listener standing in front of them? Take speed of sound to be 344 m/s.
Question2
A fellow student expresses opinion that because the Suns spectrum has only weak absorption lines of hydrogen, this element cannot be a major constituent of the Sun. How would you enlighten this person? If a red star and a blue star both have the same radius and both are the same distance from the Earth, that one looks brighter in the night sky?
Question3
An anchor hold the boat stationary on a river forms the 30º angle with the river bottom. The anchor line is 100 meters long. Assume the river has a uniform depth, how deep is the river directly below the boat?