The set of spectral lines that we see in a stars spectrum depends on the stars:
atomic structure. chemical composition. rotation rate.
Compared to the Sun, a star whose spectrum peaks in the infrared is:
A spectral line that appears at a wavelength of 321 nm in the laboratory appears at a wavelength of 328 nm in the spectrum of a distant object. We say that the object's spectrum is:
If you heat a gas so that collisions are continually bumping electrons to higher energy levels, when the electrons fall back to lower energy levels that gas produces>
an absorption line spectrum. an emission line spectrum. X rays. radio waves. thermal radiation.
When white light passes through a cool cloud of gas, we see
thermal radiation. infrared light. an absorption line spectrum. visible light. an emission line spectrum.
Which of the following objects is not a close approximation of a thermal emitter> a filament in a light bulb a planet a star hot, thin gas you
Thermal radiation is defined as:
radiation in the form of emission lines from an object. radiation in the infrared part of the spectrum. radiation that depends only on the emitting object's temperature. radiation that is felt as heat. radiation produced by a hot object
Which of the following statements about thermal radiation is always true> A hot object emits less total radiation than a cool object. A hot object emits more radio waves than a cool object. A hot object emits more total radiation than a cool object. A hot object emits more X rays than a cool object. A hot object emits more total radiation per unit surface area than a cool object
Which of the following statements about thermal radiation is always true?
A hot object emits photons with a longer wavelength than a cool object. A hot object emits more radio waves than a cool object. A hot object emits more X rays than a cool object. A hot object emits photons with a higher average energy than a cool object.
A gas heated to millions of degrees would emit: an equal amount of all wavelengths of light. mostly X rays. mostly ultraviolet light. mostly radio waves. no light, because it is too hot.
We can learn a lot about the properties of a star by studying its spectrum. All of the following statements are true except one. Which one? We can identify chemical elements present in the star by recognizing patterns of spectral lines that correspond to particular chemicals. We can look at Doppler shifts of spectral lines to determine the star's speed toward or away from us. The peak of the star's thermal emission tells us its temperature: Hotter stars peak at shorter (bluer) wavelengths. The total amount of light in the spectrum tells us the star's radius.
The spectra of most galaxies show redshifts. This means that their spectral lines: have wavelengths that are longer than normal. have a higher intensity in the red part of the spectrum. always are in the red part of the visible spectrum. have wavelengths that are shorter than normal. have normal wavelengths, but absorption of light makes them appear red.
From labortary measurements, we know that a