Sapling #4

[StephanieGrigorian2J]

HI! I was able to do the first part of this question by finding the work function but I can't seem to figure out the second question:
"A metal was exposed to photons at a frequency of 1.11x10^-15 s^-1, electrons were emitted with a maximum kinetic energy of 3.60x10^-19 J. Calculate the work function. What is the maximum number of electrons that could be ejected from this metal by a burst of photons (at some other frequency) with a total energy of 2.63x10^-7 J?"

[Cooper Kinne 2E]

Hey! I believe you just need to divide the total energy by the work function you got in the previous step (energy/energy needed per electron removed= max amount of electrons that could be removed)

[Lilly Catarozoli 1B]

You just need to divide the total energy by the work function from the step yu did before and then you should get the answer!

[Sarah Huang 3A]

HI! I was able to do the first part of this question by finding the work function but I can't seem to figure out the second question:
"A metal was exposed to photons at a frequency of 1.11x10^-15 s^-1, electrons were emitted with a maximum kinetic energy of 3.60x10^-19 J. Calculate the work function. What is the maximum number of electrons that could be ejected from this metal by a burst of photons (at some other frequency) with a total energy of 2.63x10^-7 J?"

Hi Stephanie!

With the answer you got for the previous part, you use it to divide the total energy they gave you since you know the work function to remove an electron. By dividing the total energy by the work function you found, you'll get the total amount of electrons that will be ejected.

And for clarification, the total energy is the total amount of energy that the burst of photons give altogether, so you don't need to worry about the energy of each photon from that singular burst.

I hope that helps!

[StephanieGrigorian2J]

Thank you so much for the help guys! :)

[rhettfarmer-3H]

So the work function is found using the basic equation Ek=ep-work function. So to E of the photon convert the frequency to energy as we have been doing with the e=hv. Then basic math. As we arrange the value to the correct spot. Then to get the photons remember E of the photon is J/Photon so when you divide it by Joules it turns out to be just photons.

[IreneSeo3F]

For the second part of the question, you would divide the total energy by the value you got for the work function. Total Energy (J) / Work Function (J/photon) = Number of electrons (photons)

[Juliana Rosales 1H]

I had the same trouble with this problem but when i tried to use the equation I still couldn't get the right answer. I was confused about the second part too because I didn't know what to do lol.

[Diana Aguilar 3H]

Thanks so much everyone for the explanation! I was also having trouble solving this problem, but now I see what I was doing wrong.