The wavelength of the sodium D line is 589 nm. What are the frequency and the wavenumber for this line?

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

Define dew point. i am writing this part to be able to ask the question

What substance has a mass of 9.5g and volume of 2.1cm^3