BACHELOR OF SCIENCE (HONS) Study Guide - Rectilinear Propagation, Fresnel Diffraction, Fresnel Lantern

a 500 lines per mm diffraction grating is illuminated by light of wavelength 510 nm.

500 lines per mm diffraction grating are illuminated by the light of wavelength 510 nm.
1. How many diffraction orders are seen?
mmax= __________

2. What is the angle of each diffraction order?

θ = _______o

A 500 lines per mm diffraction grating is illuminated by light of wavelength 650 nm . What is the angle of each diffraction order starting from zero diffraction order to the maximum visible diffraction order?

Sound exits a diffraction horn loudspeaker through a rectangularopening. The loudspeaker is mounted outside on a pole. In winter,when the temp is 273K, the
diffraction angle is 15.0 degrees. What is the diffraction anglewhent he temp is 311K? I am just unsure what equation to use.