Solve Photoelectric Effect: Find Work Function & Planck's Constant

  • Thread starter Thread starter patapat
  • Start date Start date
AI Thread Summary
To solve the photoelectric effect problem, the work function of potassium and Planck's constant need to be determined using given wavelengths and stopping potentials. The relevant equation is eV₀ = hf - φ, where φ is the work function. The stopping potentials for 450 nm and 300 nm light are 0.52 V and 1.90 V, respectively, indicating that the work function remains constant across both scenarios. By setting up two equations based on the stopping potentials and solving for Planck's constant first, the work function can then be calculated. This method effectively utilizes the relationship between energy, frequency, and the work function.
patapat
Messages
20
Reaction score
0

Homework Statement


When light of wavelength 450 nm is shone on potassium, photoelectrons with stopping potential of 0.52 V are emitted. If the wavelength of the incident light is changed to 300 nm, the stopping potential is 1.90 V. Using only these numbers together with the values of the speed of light and the electron charge, do the following.
(a) Find the work function of potassium
(b) Compute a value for Planck's constant.

Homework Equations


eV_{0}=hf-\phi


The Attempt at a Solution


I'm not sure how to do this problem. Since they ask us to compute a value for Planck's constant I am not sure that we actually use the equation stated above. I assume that the work function is the same for both cases of wavelength and stopping potential, but I'm not sure what the relationship is.
Thanks in advance for the help.

-pat
 
Physics news on Phys.org
it should be V_0 not V^0, thanks.
 
You can start with (b) and then do (a). Have two equations of (phi) = hf - eV_o, and set them equal to each other since they each the same phi value. You should then be able to solve for h. Then plug h into one of the equations to find phi
 

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

Determining Planck's Constant With Photoelectric Effect
Replies
7
Views
5K
Calculating Stopping Potential in Photoelectric Effect Experiment
Replies
4
Views
2K
Photoelectric Effect Graph and Work Function Questions
Replies
25
Views
4K
Photoelectric Effect - Laboration
Replies
1
Views
2K
Photoelectric effect calculation
Replies
8
Views
3K
Photoelectric effect find velocity?
Replies
1
Views
2K
Question concerning photoelectric effect lab
Replies
1
Views
1K
Photoelectric Effect - Maximum Wavelength
Replies
1
Views
3K
Photoelectric effect and Planck's Constant
Replies
8
Views
2K
Photoelectric effect, calculating work function
Replies
4
Views
5K

Hot Threads

Recent Insights

Back
Top