A plane transmission grating is ruled with 4500 slits/cm . Assume normal incidence. The α and β lines emitted by atomic hydrogen have wavelengths of 656 nm and 486 nm , respectively. Compute the angular separation in degrees between these lines in the first-order spectrum and second-order spectrum.

The speed of light in a material is 0.50 c. what is the critical angle of a light ray at the interface between the material and a vacuum?

Water is siphoned from a large tank and discharges into the atmosphere through a 50-mm diameter tube. the end of the tube is b = 2.1 m below the tank bottom which is a = 7.4 m deep, and viscous effects are negligible. determine the maximum height h over which the water can be siphoned without cavitation occurring. atmospheric pressure is 101.4 kpa, and the water vapor pressure is 1.79 kpa (absolute)

What is a subatomic particle with a negative charge and very little mass?