Describe the spectrum of each of the following:
starlight reflected by dust,
a star behind invisible interstellar gas, and
an emission nebula.

What is the order of the moon, earth, and sun in a lunar eclipse and a solar eclipse?

Which of the following elements is in the same period as phosphorus? a. carbon c. nitrogen b. magnesium d. oxygen select the best answer from the choices provided a b c d

Why can blue light and yellow light combine to produce white light? question 17 options: they are both primary colors of light. they absorb each other's wavelengths. because blue, yellow, and white are primary colors. they are complementary colors of light.