## Photoelectric effect [ENDORSED]

Kevin Hernandez 3A
Posts: 21
Joined: Fri Sep 29, 2017 7:06 am

### Photoelectric effect

This and the following question relates to the same metal used in a series of photoelectric experiments.

A. If 3.607 x 10-19 J is required to remove an electron with zero kinetic energy from a metal surface, what would be the longest wavelength light that could do this?

a) KE= energy of photon - work function
4.200x10^-19= Ep - 3.607x10^-19
Ep= 7.807x10^-19

b) Ep= hv
7.807x10^-19= 6.63x10^-34(v)
v=1.18x10^15

c)c=wavelenght(v)
3.00x10^18=(w)1.18x10^15
w=
How do you convert m to nm??

Kaileigh Yang 2I
Posts: 49
Joined: Sat Jul 22, 2017 3:00 am

### Re: Photoelectric effect  [ENDORSED]

1 nm = 10^-9 m

Camille 4I
Posts: 57
Joined: Sat Aug 24, 2019 12:18 am

### Re: Photoelectric effect

Where did you get the number 4.200x10^-19 from?

ramiro_romero
Posts: 90
Joined: Sat Sep 07, 2019 12:16 am

### Re: Photoelectric effect

You convert from nm to m by mnultiplying by 10^-9. However, I am much more concerned as to how you got your value for the energy of a photon. Your kinetic energy is specified at a value of zero. You should've gotten the work function equal to the energy of the photon (since there's no excess energy).

Ep = (3.607 x 10^-19)

ShreyaKannan1B
Posts: 51
Joined: Wed Sep 11, 2019 12:15 am

### Re: Photoelectric effect

Camille 4I wrote:Where did you get the number 4.200x10^-19 from?

Yeah I don't get that either.

Charlene D 3I
Posts: 38
Joined: Wed Sep 30, 2020 9:54 pm

### Re: Photoelectric effect

ShreyaKannan1B wrote:
Camille 4I wrote:Where did you get the number 4.200x10^-19 from?

Yeah I don't get that either.

I believe he got that number from the next question (#32) that's related to this one. However the problem can be solved without this information.

Giselle_zamora_3E
Posts: 12
Joined: Wed Nov 13, 2019 12:18 am

### Re: Photoelectric effect

for part a, would you use some form of variation id c=(lambda)(frequency) ?

Kevin Hernandez 3A wrote:This and the following question relates to the same metal used in a series of photoelectric experiments.

A. If 3.607 x 10-19 J is required to remove an electron with zero kinetic energy from a metal surface, what would be the longest wavelength light that could do this?

a) KE= energy of photon - work function
4.200x10^-19= Ep - 3.607x10^-19
Ep= 7.807x10^-19

b) Ep= hv
7.807x10^-19= 6.63x10^-34(v)
v=1.18x10^15

c)c=wavelenght(v)
3.00x10^18=(w)1.18x10^15
w=
How do you convert m to nm??