Explain Youngs double slit experiment.

Explain how Young utilized the double slit experiment to discover that light travels in waves. How was it possible that he was able to measure the very small wavelengths?

Describe Michelsons interferometer

Describe and explain how Michelson used his interferometer to measure the densities of a gas in a cylinder.

Calculating the velocity of a pion given its average lifetime.

The pion has an average lifetime of 26.0 ns. In order for it to travel 10.0 m, how fast must it move?

Magnetism

A wire is tightly wrapped around a cylinder to form a solenoid. What is the magnetic field at a point P far enough away so that the fringing field is zero? See attached file

Clarification

A wire is tightly wrapped around a cylinder to form a solenoid. What is the magnetic field at a point P far enough away so that the fringing field is zero? Same problem but we are assuming the solenoid is finite. Further, I don't understand how your derivations apply to choices I must pick from