Threshold Frequency Calculation: 3.33eV Work Function

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To find the threshold frequency with a work function of 3.33 eV, first convert the work function to joules, resulting in 5.33 × 10^-19 J. The threshold frequency can be calculated using the equation E = hf, where E is the energy required to overcome the work function. After determining the energy difference between the electron's energy (0.511 MeV) and the work function, the threshold frequency is found to be 1.226 × 10^21 Hz. The minimum frequency can be derived by dividing the threshold frequency by 2π, yielding 1.951 × 10^20 Hz. This process effectively demonstrates how to calculate threshold and minimum frequencies based on the work function.
harhar
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How would I find the threshold frequency if the work function is 3.33eV?
I know how to calculate minimum frequency.
 
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K = \phi - hf_0
where K is K.E.
Now K>0
therefore threshold frequency will be when K=0
 


To find the threshold frequency, you can use the equation E = hf, where E is the energy (in electron volts, eV), h is Planck's constant (4.1357 × 10^-15 eV·s), and f is the frequency (in hertz, Hz).

Since the work function is given in eV, you can convert it to joules by multiplying it by the conversion factor 1.6022 × 10^-19. This gives a work function of 5.33 × 10^-19 J.

To find the threshold frequency, you need to first calculate the energy required to overcome the work function. This can be done by subtracting the work function from the energy of an electron, which is 0.511 MeV (million electron volts).

So, the energy required would be 0.511 MeV - 3.33 eV = 0.50767 MeV.

Now, you can plug this energy into the equation E = hf and solve for f.

0.50767 MeV = (4.1357 × 10^-15 eV·s) f

Solving for f, you get a threshold frequency of 1.226 × 10^21 Hz.

To find the minimum frequency, you can simply divide the threshold frequency by 2π, as the minimum frequency is equal to the threshold frequency divided by 2π.

So, the minimum frequency would be 1.226 × 10^21 Hz / 2π = 1.951 × 10^20 Hz.

In summary, to find the threshold frequency when the work function is 3.33eV, you would first convert the work function to joules, subtract it from the energy of an electron, and then solve for the frequency using the equation E = hf. This would give you a threshold frequency of 1.226 × 10^21 Hz. The minimum frequency can be found by dividing the threshold frequency by 2π, giving a value of 1.951 × 10^20 Hz.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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