Fire trucks have the word FIRE written two ways, as seen here, on the front of the truck. Why is that?

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?

What are the applications of electromagnetic waves

Which branches of natural science include the study of an organism that lived 10 million years ago