pbm with photoelectrons

Photons of energy 5e.V are incident on cathode.Electrons reaching the anode have kinetic energies varying from 6e.V to 8e.V.wat is the workfunction of the metal.Electrons r acc through a potential difference of 5V

22 Answers

3
msp ·

gagar sir u have given a wrong answer

3
msp ·

sorry sir i was wrong while i typed..

1
gagar.iitk ·

is W=2ev just tell me

11
Anirudh Narayanan ·

Sorry machan. Didn't see your reply [2]

11
Anirudh Narayanan ·

Energy provided is 5eV and energy provided by photons is 5eV

So work function is 10 - 8 = 2eV

Sankara, I know it's wrong but is this the right answer?[3]

3
msp ·

the soln is

K.E.max=5+5-φ

therefore φ=2e.v

3
msp ·

u didnt consider that the electrons are accelerated by a potential difference of 5 V

1
gagar.iitk ·

some one plz tell me where i am losing the problem

1
gagar.iitk ·

the energies of electrons varying from 6ev to 8ev so the min energy of electron is 6 ev so energy given by the battery is 6 ev so max kin energy of electron ejecting from cathode is 2 ev so work function is 3 ev

3
msp ·

its all pbm with the question sir,i have edited that sir...please see it sir

1
gagar.iitk ·

might be i am not good in it but again i am getting it iam giving u my soln

1
Philip Calvert ·

hey the overall look of this writing box has somewhat changed!!
sorry sankara can't see your image

1
gagar.iitk ·

philip try to look at the range it will give the potential of the battery then u can calculate the ans

1
gagar.iitk ·

work fn=3ev

11
Anirudh Narayanan ·

Won't the work function be maximum K.E - incident energy?

Because maximum KE is obtained when the photo electron has to overcome only the work function [1]

3
msp ·

can u explain me the question:P

1
Philip Calvert ·

i think in the diagram we can see that there will be an electric field acting as well!!
but nothin else is given [2]

3
msp ·

how can be the kinetic energy of the electrons greater than that of the energy of the incident light.

62
Lokesh Verma ·

it is fixed sankara.. there was a small bug due to an upgrade.. in the post sender..

3
msp ·

no account at orkut

1
Philip Calvert ·

upload the image in orkut(if u have account) and use image link it will show up perfectly

3
msp ·

philip i have already inserted the image 2 times.but it is not showed in the post, so confused.......

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