Many extrusive volcanic rocks contain holes which have formed from: underwater eruptions, acidic reactions, quartz crystals, escaping gases.

What type of light does this light bulb produce most (i.e. at what wavelength does the spectrum have maximum intensity)?

Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excited‑state hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j

Which of the following is a measure of the amount of light a star directly emits?               a.  luminosity    b.  intensity    c.  wavelength    d.  brightness