The neutron beam is used in diffraction experiments on solid crystals. estimate the kinetic energy (in eV) in the neutron beam and compare it with the kinetic energy of an ideal gas in equilibrium at room temperature

Electrons with a speed of 2.6 x 106 m/s pass through a double-slit apparatus. Interference fringes are detected with a fringe spacing of 5.8 mm. What will the fringe spacing be if the electrons are replaced by neutrons with the same speed? What speed must neutrons have to produce interference fringes with a fringe spacing of 5.8 mm?

In Millikan's oil-drop experiment, one looks at a small oil drop held motionless between two plates. Take the voltage between the plates to be 2161 V and the plate separation to be 2 cm. The oil drop (of density 0.81 g/cm3) has a diameter of 4.0 ×10-6 m. Find the charge on the drop, in terms of electron units.  e

Consider a model of an electron as a hollow sphere with radius R and the electron charge -e spread uniformly over that surface. d. Use Einstein’s equation relating rest mass to energy to derive a value for R. Unfortunately, your answer will be model-dependent. The traditional “Classical radius of the electron” is derived by setting the electrostatic work to be e2/(4pi e0 R)