- #1
bobbles22
- 16
- 0
Hi all,
I'm trying to understand work functions and am working through a paper but keep coming up with the wrong answer. Can anyone point out where I'm going wrong please...
Wavelength of light incident on surface = 560 nm
Max speed of ejected electrons = 1.67 x 105 ms-1
1 eV = 1.602 x 10-19 J
I'm using 0.5mv2=hf-ø rearranged as ø=hf-0.5mv2
Putting in the figures above:
=(6.63 x 10-34) x (1 / (5.6 x 10-19)) - 0.5 (1.67 x 105)2 x 9.109 x 10-31
= 1.18 x 10-27 - 12.70 x 10-21 = -1.27 x 10-20 J
I'm sure I'm not meant to come up with a negative answer.
Many thanks for any assistance you can give.
Bob
I'm trying to understand work functions and am working through a paper but keep coming up with the wrong answer. Can anyone point out where I'm going wrong please...
Wavelength of light incident on surface = 560 nm
Max speed of ejected electrons = 1.67 x 105 ms-1
1 eV = 1.602 x 10-19 J
I'm using 0.5mv2=hf-ø rearranged as ø=hf-0.5mv2
Putting in the figures above:
=(6.63 x 10-34) x (1 / (5.6 x 10-19)) - 0.5 (1.67 x 105)2 x 9.109 x 10-31
= 1.18 x 10-27 - 12.70 x 10-21 = -1.27 x 10-20 J
I'm sure I'm not meant to come up with a negative answer.
Many thanks for any assistance you can give.
Bob
