Question

The spectrum of a star has dark absorption lines of helium superimposed on a continuous spectrum. What can you conclude from this?

a The star is made up of helium

b There is a great deal of helium in the earth’s atmosphere

c The dark lines have absorbed helium

d The light from the star has passed through a cloud of helium

Estimate the wavelength of the red line in oxygen.

Which of the following regions is the widest?

a. Ultraviolet b. Visible red c. Infrared d. X-ray

Answer 1

c. the dark lines have absorbed helium is correct

A pair of strong lines caused by Oxygen molecules that have been doubly ionized (OIII) can be found at 500.7 nm and 495.9 nm respectively. A second pair of strong lines (OII) can be found at 372.7 nm and 373.0 nm respectively

X-ray is widest