Question

1- What is the wavelength range for visible light?

2- what is continuous spectrum? what is a discrete spectrum?

Answer 1

1)

Visible light ranges from 400nm (Violet) to 700nm (red).

You can see light split into its different wavelengths by looking at a rainbow!

2)

A continuous spectrum is all wavelengths of radiation, an emission spectrum is the result of matter being heated and emitting electromagnetic radiation at discreate wavelengths according to the allowable energy levels of it's electrons

discrete spectrum is that it is an emission spectrum or absorption spectrum for which there is only an integer number (or countable number) of intensities. Atomic electronic absorption and emission spectrum are discrete, as contrasted with, for example, the emission spectrum of the sun, which is continuous. Discrete emission spectra of atoms are also referred to as emission line spectra, which show vertical lines at the frequencies (or wavelengths) of emission.