Blackbody Spectrum Post-Lab

Which of the following give off infrared radiation?

• people

• light bulbs

• stars

• teletubbies

• a heated / glowing stovetop burner

Not counting reflected light, which of the following give off visible radiation (they are luminous objects)?

• people

• light bulbs

• stars

• a heated / glowing stovetop burner

• a desk

(Q4) If you pointed an infrared sensor at the sun, would you be able to detect it? (Does the sun produces infrared energy?)

• Yes, we also feel the infrared energy as warmth on our skin.

• No.

(Q5) If you pointed an ULTRAVIOLET sensor at the sun, would you be able to detect it? (Does the sun produces UVenergy?)

• Yes, that is why we get sunburns.

• No.

In the simulation, as you go from low temperature objects (like the Earth) to high temperature objects (like the star Sirius A), what happens to the color produced?

• It transitions from not emitting light, to emitting red light, then yellow, green, and lastly violet / blue.

• It transitions from emitting blue light (the Earth), to emitting red light, then yellow, and lastly violet / blue.

• Objects go from being blue to green to red as they heat up.

(Q9) As a blackbody, what wavelength of radiation does a low-temperature star (~4000 degrees) give off? Where is the peak of electromagnetic energy it gives off?

• Infrared radiation

• ultraviolet light

• gamma rays

• visible light

(Q12) As a blackbody, what wavelength of radiation does the star SIRIUS A primarily create / give off? Where does the its electromagnetic energy reach its peak?

• Infrared radiation

• ultraviolet light

• gamma rays

• visible light

(Q13d) Who do are incandescent light bulbs (the ones with the glowing filament) considered to be wasteful?

• They are intended to give off visible light, but they actually create a large amount of heat (infrared radiation).

• They are intended to create heat, but they actually create a large amount of light (visible radiation) which is really annoying. Turn off the lights please!

(Q14g) We see the earth by reflected light, but we don't see the earth glowing except at a few spots where there is an active volcano. Why is this?

• The surface of the Earth is not hot enough to give off visible light (only infrared), but it is hot enough on the inside.

• The surface of the Earth is overpowered by the light coming from the Sun, which makes it hard to see it glowing.

• The Earth is producing large amounts of ultraviolet light, which we cannot see (but can sense with our skin).

(15h) What part of the electromagnetic spectrum would be useful to determine the surface temperature of objects such as asteroids (which do not glow)?

• Visible light

• Infrared

• Ultraviolet

• Gamma ray