Which is the part of an experiment that serves as the point of comparison for the results

What type of electromagnetic radiation has a shorter wavelength than blue light

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line

What does the symbol (–hfus) indicate in a phase change?