baer
Mar18-07, 10:20 PM
I just got back from a 3 day taekwondo tourney (first place black belt Lt. oh ya), and realized I have done no studying whatsoever for my midterm that is tomorow. I have a few questions as you might expect.. (Idont just want answers, I dont have to turn this in its just review questions for the midterm, so I need to know how to do it).
First, I know about alpha/beta decay, but what causes it to be one or the other?
If a substance contains 500 trinium atoms, half life of trinium is 12.43 years, how do I write an equation for the decay of trinium (it ejects a beta particle,dono if that matters).
An electron is ejected from the nucleus of a carbon14 atom. The energy ejected is 160 KeV, or 1,60x10^5 eV. 1 eV = 1.6x10^-19 J. What type of radioactive particle is this electron, and what element does the c14 atom become during this process (is it lead?).
Now some heat engine questions... Say engine burns 500J or heat energy, produces 150 J or work. If its running in a room at 25C temp, whats the 'hot' temp of engines cycle if I treat it as an 'ideal' heat engine (wich means no energy lost im assuming?)
Now, if a heat engine is 10% efficient when its operating at 20 degrees C, and this is the 'cold' temperature of the engines work cycle, how do I know how hot the engine must run (the highest temperature) for it to operate at this efficiency. Also if it absorbs 1000J of energy, how much of this energy is exausted at the cold temperature phase, and whats the minimum energy the engine has to have to perform 1000 J of work.
Also I cant find the SI units for efficiency or half-life anywhere =[
If you can help with any of these questions I thank you mucho!
First, I know about alpha/beta decay, but what causes it to be one or the other?
If a substance contains 500 trinium atoms, half life of trinium is 12.43 years, how do I write an equation for the decay of trinium (it ejects a beta particle,dono if that matters).
An electron is ejected from the nucleus of a carbon14 atom. The energy ejected is 160 KeV, or 1,60x10^5 eV. 1 eV = 1.6x10^-19 J. What type of radioactive particle is this electron, and what element does the c14 atom become during this process (is it lead?).
Now some heat engine questions... Say engine burns 500J or heat energy, produces 150 J or work. If its running in a room at 25C temp, whats the 'hot' temp of engines cycle if I treat it as an 'ideal' heat engine (wich means no energy lost im assuming?)
Now, if a heat engine is 10% efficient when its operating at 20 degrees C, and this is the 'cold' temperature of the engines work cycle, how do I know how hot the engine must run (the highest temperature) for it to operate at this efficiency. Also if it absorbs 1000J of energy, how much of this energy is exausted at the cold temperature phase, and whats the minimum energy the engine has to have to perform 1000 J of work.
Also I cant find the SI units for efficiency or half-life anywhere =[
If you can help with any of these questions I thank you mucho!