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Can you please help me with this Physics question about the Photoelectric effect? I

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I've used what I could find on the equation sheet, so I used Einstein's photoelectric equation and E=hf.

I don't really get what I need to work out and why, so if you could explain that to me then that would be great. Using the photoelectric equation, I was trying to find v so I rearranged it to get hf-ϕ = 1/2mv2 (which is kinetic energy). I was then trying to rearrange that to get v on it's own, but I don't know what the value for m is so I'm a bit stuck.

If anyone could explain it to me I'd be very greatful.

Thank you
Original post by vector12
unnamed (4).jpg

I've used what I could find on the equation sheet, so I used Einstein's photoelectric equation and E=hf.

I don't really get what I need to work out and why, so if you could explain that to me then that would be great. Using the photoelectric equation, I was trying to find v so I rearranged it to get hf-ϕ = 1/2mv2 (which is kinetic energy). I was then trying to rearrange that to get v on it's own, but I don't know what the value for m is so I'm a bit stuck.

If anyone could explain it to me I'd be very greatful.

Thank you


m is the mass of the electron or photoelectron.

I suggest you find a text to study what is photoelectric effect. It seems that you doing what is known as plug and play way of solving a problem.
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vector12
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Original post by Eimmanuel
m is the mass of the electron or photoelectron.

I suggest you find a text to study what is photoelectric effect. It seems that you doing what is known as plug and play way of solving a problem.


I know what it is, I've been taught in lessons but I don't have any experience of practice questions. I've got my 1/2mv^2 = 3.245 x 10^-19, so I've doubled that to get mv^2 = 1.989 x 10^-18. I've then rearranged to get V = square root of (1.989x10^-18 / 9.11x10^-31), where m=9.11x10^31 and I get an answer of 1477604.493 somehow.
Original post by vector12
I know what it is, I've been taught in lessons but I don't have any experience of practice questions. I've got my 1/2mv^2 = 3.245 x 10^-19, so I've doubled that to get mv^2 = 1.989 x 10^-18. I've then rearranged to get V = square root of (1.989x10^-18 / 9.11x10^-31), where m=9.11x10^31 and I get an answer of 1477604.493 somehow.


1/2mv^2 = 3.245 × 10^-19
mv^2 =2 × 3.245 × 10^-19 = 6.49 × 10^-19

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