ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: Elnino_Gerrard on November 02, 2010, 11:30:01 pm
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Tsfx 2009. When it gives a graph of photocurrent versus voltage. The grap drawn is of orange light of intensity 5.0 w/m^2
Now it says, draw a graph if violet light was used.
1) Stopping voltage would be greater
2) The photocurrent is also lower??? (can someone please explain why this is the case?)
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since violet light has a greater energy, given by a higher frequency, it would require less photons to produce a 5.0 Wm^-2 light.
Watts = N*Energy/Time
Watts/Metres^2 = (N*Energy)/(Time*Metres^2)
where N is the number of photons.
Since Energy is higher (with the violet light), the N value decreases to give the same amount of intensity.
Since incident photons are now lower in number, the photocurrent also decreases.
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ahh i see ..Thanks mate