# Help with Isaac chemistry question D3.9

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#1
The question is something to do with finding the ionisation energy from a wavelength value in nanometres and a value in electronvolts. I don't do physics so this really confused me - and I emailed support for an explanation but it still made no sense.

https://isaacphysics.org/questions/c...hem_16_book_d3

thanks for the help
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1 year ago
#2
(Original post by BlueNova42)
...
Ejection at max KE refers to the 1st ionisation energy. Energy of 1 photon of UV (hc/λ) minus max KE, gives 1st ionisation energy for 1 atom of the element (in kJ). Multiply by avogadro's constant for kJ/mol. Site wants ans to 2 s.f (540). 1 nm = 10^-9 m, 1 eV = 1.6*10^-19 J
Last edited by Physics Enemy; 1 year ago
1
#3
(Original post by Physics Enemy)
Ejection at max KE refers to the 1st ionisation energy. Energy of 1 photon of UV (hc/λ) minus max KE, gives 1st ionisation energy for 1 atom of the element (in kJ). Multiply by avogadro's constant for kJ/mol. Site wants ans to 2 s.f (540). 1 nm = 10^-9 m, 1 eV = 1.6*10^-19 J
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