Australia has 3 a’s but all pronounced differently how?

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.

3. which is not a primary color of light? blue red green yellow