Noob to forum, + unsolveable physics question

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adam_972
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Hi guys, new to the forum! Currently studying physics,biology, chemistry and business at as! I'm stuck on this physics question, any help would be greatly appreciated!

In a 1 kW laser, 2.3x1013 photons pass a fixed point each second. Calculate


a) The energy of each photon

4.35x10^-11 J

b) The frequency of each photon

6.56x10^22 Hz

A photon produced by this laser undergoes pair production, producing a muon / antimuon pair. Calculate:

c) The kinetic energy of each particle produced


I'm stuck on C, any help would be appreciated

So for photon energy I have 4.35x10^-11J

Rest energy for muon/antimuon pair= 2(105.659), convert into joules: 211.318 x (1.6x10^-19)= 3.381x10^-17

Then kinetic energy, (4.35x10^-11) - (3.381x10^-17)= (4.349x10^-11) / 2 divide by 2 for each particle=2.175x10^-11

My answer is still wrong?
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username1560589
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Rest energy of muon is 105MeV=105x106​eV
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adam_972
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Thanks, sorry I didn't put the units. I got the rest energy to be 105.659Mev which in joules for 2 muons is 3.381x10^-17 J (If my calculations are correct)
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Phichi
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[
(Original post by adam_972)
I'm stuck on C, any help would be appreciated

So for photon energy I have 4.35x10^-11J

Rest energy for muon/antimuon pair= 2(105.659), convert into joules: 211.318 x (1.6x10^-19)= 3.381x10^-17

Then kinetic energy, (4.35x10^-11) - (3.381x10^-17)= (4.349x10^-11) / 2 divide by 2 for each particle=2.175x10^-11

My answer is still wrong?
Don't forget that 1\, eV = 1.6\times 10^{-19}\, J

Your rest energy is 2(105.659)\, MeV \equiv 2(105.659)\times 10^{6} \, eV

Then continue.
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username1560589
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(Original post by adam_972)
Thanks, sorry I didn't put the units. I got the rest energy to be 105.659Mev which in joules for 2 muons is 3.381x10^-17 J (If my calculations are correct)
No, I got 3.381x10-11​J.
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adam_972
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Ahhh thank you! I was converting mev straight into joules. School boy error haha!
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