What is the third smallest non-zero thicknesses (in nm) of soapy water ( n=1.33 ) on Plexiglas (n=1.50) if it appears green (constructively reflecting 520-nm light) when illuminated perpendicularly by white light?

How many neutrons does plutonium -196 with an atomic number of 78.

A14 kg rock starting from rest free falls through a distance of 5.0 m with no air resistance. find the momentum change of the rock caused by its fall and the resulting change in the magnitude of earths velocity. earth mass is 6.0 * 10^24 kg. show your work assuming the rock earth system is closed.

When using the scientist method, which step comes last?