One of the pieces of evidence supporting energy quantization was the line spectra of elements. Why does this demonstrate energy quantization? a) Photons are packets of energy that act both as a particle and a wave.
b) The spectra is continuous and shows emission at all wavelengths.
c) There are sharp emission lines demonstrating discrete energy levels.
d) All compounds emit light in the ultraviolet and visible regions specifically.

c) There are sharp emission lines demonstrating discrete energy levels.

Explanation:

When an element emits energy in the form of radiation, it produces a spectrum of colors on a photographic plate. This spectrum can either be continuous or discrete. In continuous spectrum the spectrum continues without any discrimination between two regions. This represents the continuous emission of radiation, and thus the continuous emission of energy without any break.

On the other hand, the line spectrum consists of discrete and sharp lines, which shows the emission of radiation in a certain amount in a certain time, with a break between emission. Hence, the line spectra supports the quantization of energy.

The correct option is:

c) There are sharp emission lines demonstrating discrete energy levels.

the answer is d. 74.02