homework

Interference Lab Post-Lab Knowledge Check PHYS 242

1. Above is a diagram of the wavefronts due to two sources. What is the source separation in your diagram? Not everyone's printout or screen image will be the same size so express your answer in terms of the wavelength. For instance, the two sources might be 1, 2, or 3 wavelengths apart. If the separation is not a whole number of wavelengths enter a decimal number, for instance 2.5 instead of 2 1/2.

2. Using different symbols (or different colors), mark the places at which for the instant shown:

• the displacement of the water surface is zero (i.e., at its equilibrium level) • the displacement of the water surface is the greatest above equilibrium • the displacement of the water surface is the greatest below equilibrium • On your diagram, mark the nodal lines and the lines of constructive interference.

Hint: Look for patterns that will help you identify all of these points.