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'matter for this circuit and working of touch alarm according to this circuit — Preceding unsigned comment added by 14.98.20.92 ( talk) 01:27, 6 June 2014 (UTC)
How do scientists discover cures for diseases and things like that? 203.45.159.248 ( talk) 07:18, 6 June 2014 (UTC)
The intensity of a beam of radiation travelling in a certain direction is related to its energy density by the formula , and it produces a radiation pressure of . Now, I know that if the radiation isn't travelling in a certain direction, ie it's thermalized and travelling outwards in all directions equally, then the radiation pressure will become . Will the formula for the intensity also pick up a factor of 1/3? 24.37.154.82 ( talk) 15:18, 6 June 2014 (UTC)
What's the mechanism behind things like sparks, lightning, St. Elmo's fire, etc.? I've heard two different explanations, both of which seem reasonable:
1) Stray electrons are accelerated by the potential difference created between eg the thundercloud and the ground. These electrons attain enough energy to ionize air molecules, creating more stray electrons which ionize more air molecules, and so on, creating an avalanche of electrons.
2) The potential difference is great enough to ionize the air (without needing say stray electrons), creating free charges which can then be accelerated by the potential difference to create a current.
Which one is right? 65.92.6.219 ( talk) 21:47, 6 June 2014 (UTC)
Science desk | ||
---|---|---|
< June 5 | << May | June | Jul >> | June 7 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
'matter for this circuit and working of touch alarm according to this circuit — Preceding unsigned comment added by 14.98.20.92 ( talk) 01:27, 6 June 2014 (UTC)
How do scientists discover cures for diseases and things like that? 203.45.159.248 ( talk) 07:18, 6 June 2014 (UTC)
The intensity of a beam of radiation travelling in a certain direction is related to its energy density by the formula , and it produces a radiation pressure of . Now, I know that if the radiation isn't travelling in a certain direction, ie it's thermalized and travelling outwards in all directions equally, then the radiation pressure will become . Will the formula for the intensity also pick up a factor of 1/3? 24.37.154.82 ( talk) 15:18, 6 June 2014 (UTC)
What's the mechanism behind things like sparks, lightning, St. Elmo's fire, etc.? I've heard two different explanations, both of which seem reasonable:
1) Stray electrons are accelerated by the potential difference created between eg the thundercloud and the ground. These electrons attain enough energy to ionize air molecules, creating more stray electrons which ionize more air molecules, and so on, creating an avalanche of electrons.
2) The potential difference is great enough to ionize the air (without needing say stray electrons), creating free charges which can then be accelerated by the potential difference to create a current.
Which one is right? 65.92.6.219 ( talk) 21:47, 6 June 2014 (UTC)