If the distance between slits on a diffraction grating is 0.50 mm and one of the angles of diffraction is 0.25°, how large is the path difference? nm

How many orders of bright lines does this equal for red light with a wavelength of 650 nm?

wavelengths

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 = 2.6 m below the tank bottom which is a = 6.7 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). report your answer in meters to two decimal places.