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CR-39 is a kind of plastic commonly used in lenses. So uh, don't eat it or breathe it, but you're /probably/ ok to touch it. That said, its also used in radiation detectors. Radiation is basically always bad for you (unless there's only a little bit, and then it's only a little bit bad for you). You might want to check out: http://en.wikipedia.org/wiki/CR-39 http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?sid=695746
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What is the index of refraction of CR 39?
1.498 or 1.50
Two disadvantages of using manufactured boards?
Blunt tools quickly, Thin sheets flop, Difficult to join, Edges must be concealed and hazardous dust particles.
What is the lens of eyeglasses made of?
These days people most lenses are plastic (cr-39) or poly. The cr-39 stands for the certain batch that was made, and which it was a good one, so it was kept. every once and a while you will get that person that just wants glass because it can withstand scratches more, but it's still not scratch proof.
Do you level up on Halo Reach?
Yes, Here are the ranks (in order, there are 50 all told): RankRequired no. of cRRecruit0 cRPrivate7,500 cR(+7,500 cR)Corporal10,000 cR(+2,500 cR)CorporalGrade 115,000 cR(+5,000 cR)Sergeant20,000 cR(+5,000 cR)SergeantGrade 126,250 cR(+6,250 cR)SergeantGrade 232,500 cR(+6,250 cR)Warrant Officer45,000 cR(+12,500 cR)Warrant OfficerGrade 178,000 cR(+33,000 cR)Warrant OfficerGrade 2111,000 cR(+33,000 cR)Warrant OfficerGrade 3144,000 cR(+33,000 cR)Captain210,000 cR(+66,000 cR)CaptainGrade 1233,000 cR(+23,000 cR)CaptainGrade 2256,000 cR(+23,000 cR)CaptainGrade 3279,000 cR(+23,000 cR)Major325,000 cR(+46,000 cR)MajorGrade 1350,000 cR(+25,000 cR)MajorGrade 2375,000 cR(+25,000 cR)MajorGrade 3400,000 cR(+25,000 cR)Lt. Colonel450,000 cR(+50,000 cR)Lt. ColonelGrade 1480,000 cR(+30,000 cR)Lt. ColonelGrade 2510,000 cR(+30,000 cR)Lt. ColonelGrade 3540,000 cR(+30,000 cR)Commander600,000 cR(+60,000 cR)CommanderGrade 1650,000 cR(+50,000 cR)CommanderGrade 2700,000 cR(+50,000 cR)CommanderGrade 3750,000 cR(+50,000 cR)Colonel850,000 cR(+100,000 cR)ColonelGrade 1960,000 cR(+110,000 cR)ColonelGrade 21,070,000 cR(+110,000 cR)ColonelGrade 31,180,000 cR(+110,000 cR)Brigadier1,400,000 cR(+220,000 cR)BrigadierGrade 11,520,000 cR(+120,000 cR)BrigadierGrade 21,640,000 cR(+120,000 cR)BrigadierGrade 31,760,000 cR(+120,000 cR)General2,000,000 cR(+240,000 cR)GeneralGrade 12,200,000 cR(+200,000 cR)GeneralGrade 22,350,000 cR(+150,000 cR)GeneralGrade 32,500,000 cR(+150,000 cR)GeneralGrade 42,650,000 cR(+150,000 cR)Field Marshall3,000,000 cR(+350,000 cR)Hero3,700,000 cR(+700,000 cR)Legend4,600,000 cR(+900,000 cR)Mythic5,650,000 cR(+1,050,000 cR)Noble7,000,000 cR(+1,350,000 cR)Eclipse8,500,000 cR(+1,500,000 cR)Nova11,000,000 cR(+2,500,000 cR)Forerunner13,000,000 cR(+2,000,000 cR)Reclaimer16,500,000 cR(+3,500,000 cR)Inheritor20,000,000 cR(+3,500,000 cR)
What are the ranks for halo reach?
RankInsigniaRequired no. of cRRecruit0 cRPrivate7,500 cR(+7,500 cR)Corporal10,000 cR(+2,500 cR)CorporalGrade 115,000 cR(+5,000 cR)Sergeant20,000 cR(+5,000 cR)SergeantGrade 126,250 cR(+6,250 cR)SergeantGrade 232,500 cR(+6,250 cR)Warrant Officer45,000 cR(+12,500 cR)Warrant OfficerGrade 178,000 cR(+33,000 cR)Warrant OfficerGrade 2111,000 cR(+33,000 cR)Warrant OfficerGrade 3144,000 cR(+33,000 cR)Captain210,000 cR(+66,000 cR)CaptainGrade 1233,000 cR(+23,000 cR)CaptainGrade 2256,000 cR(+23,000 cR)CaptainGrade 3279,000 cR(+23,000 cR)Major325,000 cR(+46,000 cR)MajorGrade 1350,000 cR(+25,000 cR)MajorGrade 2375,000 cR(+25,000 cR)MajorGrade 3400,000 cR(+25,000 cR)Lt. Colonel450,000 cR(+50,000 cR)Lt. ColonelGrade 1480,000 cR(+30,000 cR)Lt. ColonelGrade 2510,000 cR(+30,000 cR)Lt. ColonelGrade 3540,000 cR(+30,000 cR)Commander600,000 cR(+60,000 cR)CommanderGrade 1650,000 cR(+50,000 cR)CommanderGrade 2700,000 cR(+50,000 cR)CommanderGrade 3750,000 cR(+50,000 cR)Colonel850,000 cR(+100,000 cR)ColonelGrade 1960,000 cR(+110,000 cR)ColonelGrade 21,070,000 cR(+110,000 cR)ColonelGrade 31,180,000 cR(+110,000 cR)Brigadier1,400,000 cR(+220,000 cR)BrigadierGrade 11,520,000 cR(+120,000 cR)BrigadierGrade 21,640,000 cR(+120,000 cR)BrigadierGrade 31,760,000 cR(+120,000 cR)General2,000,000 cR(+240,000 cR)GeneralGrade 12,200,000 cR(+200,000 cR)GeneralGrade 22,350,000 cR(+150,000 cR)GeneralGrade 32,500,000 cR(+150,000 cR)GeneralGrade 42,650,000 cR(+150,000 cR)Field Marshall3,000,000 cR(+350,000 cR)Hero3,700,000 cR(+700,000 cR)Legend4,600,000 cR(+900,000 cR)Mythic5,650,000 cR(+1,050,000 cR)Noble7,000,000 cR(+1,350,000 cR)Eclipse8,500,000 cR(+1,500,000 cR)Nova11,000,000 cR(+2,500,000 cR)Forerunner13,000,000 cR(+2,000,000 cR)Reclaimer16,500,000 cR(+3,500,000 cR)Inheritor20,000,000 cR(+3,500,000 cR)
How many ranks is there in halo reach?
50: RankInsigniaRequired no. of cRRecruit0 cRPrivate7,500 cR(+7,500 cR)Corporal10,000 cR(+2,500 cR)CorporalGrade 115,000 cR(+5,000 cR)Sergeant20,000 cR(+5,000 cR)SergeantGrade 126,250 cR(+6,250 cR)SergeantGrade 232,500 cR(+6,250 cR)Warrant Officer45,000 cR(+12,500 cR)Warrant OfficerGrade 178,000 cR(+33,000 cR)Warrant OfficerGrade 2111,000 cR(+33,000 cR)Warrant OfficerGrade 3144,000 cR(+33,000 cR)Captain210,000 cR(+66,000 cR)CaptainGrade 1233,000 cR(+23,000 cR)CaptainGrade 2256,000 cR(+23,000 cR)CaptainGrade 3279,000 cR(+23,000 cR)Major325,000 cR(+46,000 cR)MajorGrade 1350,000 cR(+25,000 cR)MajorGrade 2375,000 cR(+25,000 cR)MajorGrade 3400,000 cR(+25,000 cR)Lt. Colonel450,000 cR(+50,000 cR)Lt. ColonelGrade 1480,000 cR(+30,000 cR)Lt. ColonelGrade 2510,000 cR(+30,000 cR)Lt. ColonelGrade 3540,000 cR(+30,000 cR)Commander600,000 cR(+60,000 cR)CommanderGrade 1650,000 cR(+50,000 cR)CommanderGrade 2700,000 cR(+50,000 cR)CommanderGrade 3750,000 cR(+50,000 cR)Colonel850,000 cR(+100,000 cR)ColonelGrade 1960,000 cR(+110,000 cR)ColonelGrade 21,070,000 cR(+110,000 cR)ColonelGrade 31,180,000 cR(+110,000 cR)Brigadier1,400,000 cR(+220,000 cR)BrigadierGrade 11,520,000 cR(+120,000 cR)BrigadierGrade 21,640,000 cR(+120,000 cR)BrigadierGrade 31,760,000 cR(+120,000 cR)General2,000,000 cR(+240,000 cR)GeneralGrade 12,200,000 cR(+200,000 cR)GeneralGrade 22,350,000 cR(+150,000 cR)GeneralGrade 32,500,000 cR(+150,000 cR)GeneralGrade 42,650,000 cR(+150,000 cR)Field Marshall3,000,000 cR(+350,000 cR)Hero3,700,000 cR(+700,000 cR)Legend4,600,000 cR(+900,000 cR)Mythic5,650,000 cR(+1,050,000 cR)Noble7,000,000 cR(+1,350,000 cR)Eclipse8,500,000 cR(+1,500,000 cR)Nova11,000,000 cR(+2,500,000 cR)Forerunner13,000,000 cR(+2,000,000 cR)Reclaimer16,500,000 cR(+3,500,000 cR)Inheritor20,000,000 cR(+3,500,000 cR)
What are all of the ranks in halo reach?
RankInsigniaRequired no. of cRRecruit0 cRPrivate7,500 cR (+7,500 cR)Corporal10,000 cR (+2,500 cR)Corporal Grade 115,000 cR (+5,000 cR)Sergeant20,000 cR (+5,000 cR)Sergeant Grade 126,250 cR (+6,250 cR)Sergeant Grade 232,500 cR (+6,250 cR)Warrant Officer45,000 cR (+12,500 cR)Warrant Officer Grade 178,000 cR (+33,000 cR)Warrant Officer Grade 2111,000 cR (+33,000 cR)Warrant Officer Grade 3144,000 cR (+33,000 cR)Captain210,000 cR (+66,000 cR)Captain Grade 1233,000 cR (+23,000 cR)Captain Grade 2256,000 cR (+23,000 cR)Captain Grade 3279,000 cR (+23,000 cR)Major325,000 cR (+46,000 cR)Major Grade 1350,000 cR (+25,000 cR)Major Grade 2375,000 cR (+25,000 cR)Major Grade 3400,000 cR (+25,000 cR)Lt. Colonel450,000 cR (+50,000 cR)Lt. Colonel Grade 1480,000 cR (+30,000 cR)Lt. Colonel Grade 2510,000 cR (+30,000 cR)Lt. Colonel Grade 3540,000 cR (+30,000 cR)Commander600,000 cR (+60,000 cR)Commander Grade 1650,000 cR (+50,000 cR)Commander Grade 2700,000 cR (+50,000 cR)Commander Grade 3750,000 cR (+50,000 cR)Colonel850,000 cR (+100,000 cR)Colonel Grade 1960,000 cR (+110,000 cR)Colonel Grade 21,070,000 cR (+110,000 cR)Colonel Grade 31,180,000 cR (+110,000 cR)Brigadier1,400,000 cR (+220,000 cR)Brigadier Grade 11,520,000 cR (+120,000 cR)Brigadier Grade 21,640,000 cR (+120,000 cR)Brigadier Grade 31,760,000 cR (+120,000 cR)General2,000,000 cR (+240,000 cR)General Grade 12,200,000 cR (+200,000 cR)General Grade 22,350,000 cR (+150,000 cR)General Grade 32,500,000 cR (+150,000 cR)General Grade 42,650,000 cR (+150,000 cR)Field Marshall3,000,000 cR (+350,000 cR)Hero3,700,000 cR (+700,000 cR)Legend4,600,000 cR (+900,000 cR)Mythic5,650,000 cR (+1,050,000 cR)Noble7,000,000 cR (+1,350,000 cR)Eclipse8,500,000 cR (+1,500,000 cR)Nova11,000,000 cR (+2,500,000 cR)Forerunner13,000,000 cR (+2,000,000 cR)Reclaimer16,500,000 cR (+3,500,000 cR)Inheritor20,000,000 cR (+3,500,000 cR)
What is the order rank on halo reach?
Rank Image Required no. of Credits* Recruit 0 cR Private 7,500 cR (+7,500 cR) Corporal 10,000 cR (+2,500 cR) Corporal Grade 1 15,000 cR (+5,000 cR) Sergeant 20,000 cR (+5,000 cR) Sergeant Grade 1 26,250 cR (+6,250 cR) Sergeant Grade 2 32,500 cR (+6,250 cR) Warrant Officer 45,000 cR (+12,500 cR) Warrant Officer Grade 1 78,000 cR (+33,000 cR) Warrant Officer Grade 2 111,000 cR (+33,000 cR) Warrant Officer Grade 3 144,000 cR (+33,000 cR) Captain 210,000 cR (+66,000 cR) Captain Grade 1 233,000 cR (+23,000 cR) Captain Grade 2 256,000 cR (+23,000 cR) Captain Grade 3 279,000 cR (+23,000 cR) Major 325,000 cR (+46,000 cR) Major Grade 1 350,000 cR (+25,000 cR) Major Grade 2 375,000 cR (+25,000 cR) Major Grade 3 400,000 cR (+25,000 cR) Lt. Colonel 450,000 cR (+50,000 cR) Lt. Colonel Grade 1 480,000 cR (+30,000 cR) Lt. Colonel Grade 2 510,000 cR (+30,000 cR) Lt. Colonel Grade 3 540,000 cR (+30,000 cR) Commander 600,000 cR (+60,000 cR) Commander Grade 1 650,000 cR (+50,000 cR) Commander Grade 2 700,000 cR (+50,000 cR) Commander Grade 3 750,000 cR (+50,000 cR) Colonel 850,000 cR (+100,000 cR) Colonel Grade 1 960,000 cR (+110,000 cR) Colonel Grade 2 1,070,000 cR (+110,000 cR) Colonel Grade 3 1,180,000 cR (+110,000 cR) Brigadier 1,400,000 cR (+220,000 cR) Brigadier Grade 1 1,520,000 cR (+120,000 cR) Brigadier Grade 2 1,640,000 cR (+120,000 cR) Brigadier Grade 3 1,760,000 cR (+120,000 cR) General 2,000,000 cR (+240,000 cR) General Grade 1 2,200,000 cR (+200,000 cR) General Grade 2 2,350,000 cR (+150,000 cR) General Grade 3 2,500,000 cR (+150,000 cR) General Grade 4 2,650,000 cR (+150,000 cR) Field Marshall 3,000,000 cR (+350,000 cR) Hero 3,700,000 cR (+700,000 cR) Legend 4,600,000 cR (+900,000 cR) Mythic 5,650,000 cR (+1,050,000 cR) Noble 7,000,000 cR (+1,350,000 cR) Eclipse 8,500,000 cR (+1,500,000 cR) Nova 11,000,000 cR (+2,500,000 cR) Forerunner 13,000,000 cR (+3,000,000 cR) Reclaimer 16,500,000 cR (+3,500,000 cR) Inheritor 20,000,000 cR (+3,500,000 cR)
Is americium 241 hazardous?
If used inappropriately or carelessly, Americum-241 can be hazardous. It is a radioactive material that decays by emission of an alpha particle. Alpha particles are only dangerous if they are emitted by atoms within your body, so Americium-241 is only hazardous if it gets into your body. Americium-241 is used in ionization-type smoke detectors. In that use it is not hazardous unless the smoke detector is severely abused.
When potassium-39 is bombarded by neutrons chlorine-36 is produced what other particles are emitted?
An Alpha particle
What are all of the Halo Reach ranks?
Recruit 0 cR neededPrivate 7,500 cR neededCorporal 10,000 cR neededCorporal Grade 1 15,000 cR neededSergeant 20,000 cR neededSergeant Grade 1 26,250 cR neededSergeant Grade 2 32,500 neededWarrant Officer 45,000 cR neededWarrant Officer Grade 1 78,000 cR neededWarrant Officer Grade 2 111,000 cR neededWarrant Officer Grade 3 144,000 cR neededCaptain 210,000 cR neededCaptain Grade 1 233,000 cR neededCaptain Grade 2 256,000 cR neededCaptain Grade 3 279,000 cR neededMajor 325,000 cR neededMajor Grade 1 350,000 cR neededMajor Grade 2 375,000 cR neededMajor Grade 3 400,000 cR neededLt Colonel 450,000 cR neededLt Colonel Grade 1 480,000 cR neededLt Colonel Grade 2 510,000 cR neededLt Colonel Grade 3 540,000 cR neededCommander 600,000 cR neededCommander Grade 1 650,000 cR neededCommander Grade 2 700,000 cR neededCommander Grade 3 750,000 cR neededColonel 850,000 cR neededColonel Grade 1 960,000 cR neededColonel Grade 2 1,070,000 cR neededColonel Grade 3 1,180,000 cR neededBrigadier 1,400,000 cR neededBrigadier Grade 1 1,520,000 cR neededBrigadier Grade 2 1,760,000 cR neededGeneral 2,000,000 cR neededGeneral Grade 2 2,200,000 cR neededGeneral Grade 3 2,500,000 cR neededGeneral Grade 4 2,650,000 cR neededField Marshall 3,000,000 cR neededHero 3,700,000 cR neededLegend 4,600,000 cR neededMythic 5,650,000 cR neededNoble 7,000,000 cR neededEclipse 8,500,000 cR neededNova 11,000,000 cR neededForeRunner 13,000,000 cR neededReclaimer 16,500,000 cR neededInheritor 20,000,000 cR needed
How many moles are present in260g of chromium?
1 mole Cr = 51.9961g Cr 260g Cr x 1mol Cr/51.9961g Cr = 5.0 moles Cr
