A diffraction grating has $15,000$ rulings in its $1.9 \mathrm{~cm}$ width. Determine its resolving power in first and second orders.

A $6500$ slits$/ \mathrm{cm}$ diffraction grating is $3.26 \mathrm{~cm}$ wide. If light with wavelengths near $624 \mathrm{~nm}$ falls on the grating, how close can two wavelengths be if they are to be resolved in any order? What order gives the best resolution?

Red light from a laser pointer shines directly on a narrow slit whose width is about 5 wavelengths of this light. A white screen is placed $0.1 \mathrm{~m}$ behind the slit. What is observed on the screen? $(a)$ Light that is more orange, because the wavelength shifts. $(b)$ Light that is closer to infrared, because the wavelength shifts. $(c)$ A tiny red rectangle. $(d)$ A red rectangle and dimmer red stripes on cither side of it. $(e)$ No light, because the slits are too narrow.

For diffraction by a single slit, what is the effect of increasing the wavelength?

For diffraction by a single slit, what is the effect of increasing the slit width?