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# Photoelectric effect graph watch

1. Hi, I have a graph here of the photoelectric effect, the y intercept is the work function, but what I don't understand is how can the work function be negative? That would mean the material needs negative energy which isn't possible for the photoelectric effect to occur?
2. (Original post by ᒍack)
Hi, I have a graph here of the photoelectric effect, the y intercept is the work function, but what I don't understand is how can the work function be negative? That would mean the material needs negative energy which isn't possible for the photoelectric effect to occur?
from the y-intercept to the point where y=0 that is the energy of the work function, look at the x-axis. It's not negative energy, it's energy that needs to be gained.
from the y-intercept to the point where y=0 that is the energy of the work function, look at the x-axis. It's not negative energy, it's energy that needs to be gained.
Ah ok, It's just i had Ekmax = hf - work function so when i'm plotting it, the work function is in the negatives on the graph.
So from what you're saying the work function is actually the difference between 0 on the y axis and the point at which it intercept? and that it will always be positive?
4. (Original post by ᒍack)
Ah ok, It's just i had Ekmax = hf - work function so when i'm plotting it, the work function is in the negatives on the graph.
So from what you're saying the work function is actually the difference between 0 on the y axis and the point at which it intercept? and that it will always be positive?
yeah if I'm imagining the same graph as you. Hope it made sense
yeah if I'm imagining the same graph as you. Hope it made sense
This is a google image of a the same graph, and yes it did thanks, it confused me a little, just clicked in my head then

6. (Original post by ᒍack)
This is a google image of a the same graph, and yes it did thanks, it confused me a little, just clicked in my head then

yep looks good to me, you're welcome

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