How do you confirm that the heat energy reaching your hands from a glowing bulb is being carried by radiation and not by convection?
Its science the subject
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Answer:
By Steven Holzner
Radiation is one way to transfer heat. You experience radiation personally whenever you get out of the shower soaking wet in the dead of winter and bask in the warmth of the heat lamp in your bathroom. Why? Because of a little physics, of course. The heat lamp, which you see in the figure, beams out heat to you and keeps you warm through radiation.With radiation, electromagnetic waves carry the energy. Electromagnetic radiation comes from accelerating electric charges. On a molecular level, that’s what happens as objects warm up — their molecules vibrate harder and harder, causing acceleration of electric charges.
Heat energy transferred through radiation is as familiar as the light of day; in fact, it is the light of day. The sun is a huge thermal reactor about 93 million miles away in space, and neither conduction nor convection can produce any of the energy that arrives to Earth through the vacuum of space. The sun’s energy gets to the Earth through radiation, which you can confirm on a sunny day just by standing outside and letting the sun’s rays warm your face.
Every object around you is continually radiating, unless its temperature is at absolute zero (which is a little unlikely because you can’t physically get to a temperature of absolute zero, with no molecular movement). A scoop of ice cream, for example, radiates. Even you radiate all the time, but that radiation isn’t visible as light because it’s in the infrared part of the spectrum. However, that light is visible to infrared scopes, as you’ve probably seen in the movies or on television.
You radiate heat in all directions all the time, and everything in your environment radiates heat back to you. When you have the same temperature as your surroundings, you radiate as fast and as much to your environment as it does to you. When two things are in thermal contact but no thermal energy is exchanged between them, they’re in thermal equilibrium. If two things are in thermal equilibrium, they have the same temperature.
If your environment didn’t radiate
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