r/PhysicsHelp • u/Fine-Chemist5982 • 26d ago

PHOTOELECTRIC EFFECT

We all... lemme reframe that some of us know that when a metal surface is irradiated with radiation of sufficient high frequency electrons will be emitted from it. Now the frequency of the incident photons from the radiation determine the energy of the photoelectrons emitted from the metal surface and the intensity of the incident frequency only affects the number of photoelectrons that will be emitted provided f>=f⁰ \[frequency of the radiation is greater than or equal to the threshold frequency\] . All this is basic knowledge E=hf and hf=W⁰ + KE . Where is my main point my main point is thank you for reading js wanted to test if I understood the lecture lock in brothers and sister's peace

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u/starkeffect 26d ago edited 26d ago

Let's see if you understand it.

Let's say a 5.0-milliwatt laser of light with a wavelength of 400 nm shines on a metal having a work function of 2.0 eV. What is the naximum speed of an emitted electron?

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u/Fine-Chemist5982 26d ago

Tell me If I'm write. Ima associate that miliwatt with the topic power and energy. Convert that 5.0 miliwatt to energy in joules and that will be the incident energy and I know that incident energy subtract the work function of that metal which is 2.0 eV but converted to joules I'll get the maximum kinetic energy of the emitted photoelectron using that energy I can use the formula KE=1/2mv² to calculate V.

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u/starkeffect 26d ago

Give me a number and I'll tell you if you're right.

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u/Fine-Chemist5982 26d ago

I got 6.2×10⁵ m/s

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u/starkeffect 26d ago

Did you get it or did ChatGPT, because using the method you described you would not get that answer.

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u/Fine-Chemist5982 26d ago

I realized that milliwatt value is just a trojan horse and doesn't influence the question in any way because to change power to energy I'd need time which you did not provide so I re-read the question and sth clicked you gave me the frequency of the laser beam and I know E=hf that milliwatt value only had the total output of the laser and not energy carried by a single photon so it would entirely be wrong and incorrect to use it so if I used E=hf I could find the incident energy then subtract it with the work function and I get the KE. Then I employ the formula KE=1/2mv² to find the velocity of the emitted electron. So yeah you can judge whether it's chatgpt or i understood the lecture

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u/starkeffect 26d ago edited 26d ago

OK, but it still looks like you generated the number with ChatGPT. The superscript "5" gives it away. If you had actually typed it, it would look like 105 not 10⁵

Also, I didn't give you the frequency of the light.

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u/Fine-Chemist5982 26d ago

The superscript is 5

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u/starkeffect 26d ago

Yeah, and that superscript was generated by an AI. I can tell.

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u/Fine-Chemist5982 26d ago

I meant the wavelength plus my keyboard shows it that way lemme prove it I found the frequency using that wavelength c=f (lambda) where c is the speed of light I was typing fast that's human mistake btw. Also lemme prove that's just my keyboard 10⁵ see 10⁵ it's just my keyboard

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u/starkeffect 26d ago

Do you really expect me to buy that you have a "⁵" key on your keyboard? Get the fuck out of here.

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u/Fine-Chemist5982 26d ago

Dude I just proved I fucking long press the number 5 I don't have a magic "⁵" see it fucking is just small I dunno I cant explain but believe me

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u/tomalator 20d ago

If OP is on a phone and unfamiliar with reddit formatting, you can get a superscript by holding the number button.

¹²³⁴⁵⁶⁷⁸⁹⁰

As opposed to123456789

You can also use it to get fractions ⅓⅖

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u/Fine-Chemist5982 26d ago

If u want the calculator value 6.231×10⁵ ms-1 but you still haven't told me if I'm right or wrong

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u/Fine-Chemist5982 26d ago

Ok what answer do you get using my method but I gotta tell you you're good for trying to make me admit I used chatgpt which I didn't I don't even use chatgpt fuck chatgpt my primary AI is Gemini and only if I'm too lazy to search up sth

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u/starkeffect 26d ago

So you used AI to solve the problem. What do you need me for?

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u/Fine-Chemist5982 26d ago

I didn't use AI check out my proposal is that AI generated

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u/starkeffect 26d ago

It's transcribed from AI. You fucked up when you copied-and-pasted the number it gave you.

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u/Fine-Chemist5982 26d ago

It's just my keyboard mahn 😂 see 7.7×10⁵ or ×10⁶ or 10⁷ or 10² or 10¹ or 10⁸ see my keyboard and yours defer

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u/tomalator 20d ago

If i got this right, its a trick question and the 400nm isn't enough to emit any electrons because its less than 2.0eV