Physics - Modern Physics (3 of 26) The Photoelectric Effect

[@johntindell9591]

Thank you so much. Please keep continuing your craft. We are all waiting for your videos :)

[@cd8836]

Thank you! I’ve been reading my textbook a lot, but seeing worked examples helps me really understand. For some reason the words don’t make sense to me until I see your worked examples and then I understand the theory. Backwards perhaps, but that’s how it seems to work for me. Thank you again!

[@MichelvanBiezen]

That is how it worked for me when I was a student. (I think that is how most people learn).

[@Sandysan11111]

You are super awesome in breaking down the information to be absorbed

[@jordanflores1785]

When ou plugged in the values for hf/lambda - W , why did you also put the conversion factor for joules in the denominator?

[@MichelvanBiezen]

Because we wanted to convert from standard units of Joules to units of eV (electron volts). (Since the work function was expressed in eV. )

[@loukmenbelkhiri7917]

بارك الله للك علي جهدك

[@MrAdy0207]

what if it was a higher speed? should i apply the formula for mass in terms of the speed of light in this case ?

[@MichelvanBiezen]

If the speed was much higher, you would have to take the relativistic effects into account. Note that the rest mass energy of an electron is 511, 000 eV, thus when the incoming photon has an energy of 5,000 eV or higher (1% of the rest mass energy), then the relativistic effects begin to take effect.

[@MrAdy0207]

Michel van Biezen Thank you ! :)

[@mysteriousworld2529]

Thanks a lot sir

[@naturalDisplay21]

very helpful

[@syahrilsabtu1758]

hi sir, is it got another formula to find the Velocity of KE .?

[@MichelvanBiezen]

At non-relativistic speeds we use KE = (1/2) mv^2

[@jimkeller3868]

Great, but didn't understand the whole "relativistic velocity" thing.

[@MichelvanBiezen]

Whenever objects, including electrons, travel very fast, (close to the speed of light), they experience relativistic effects in time and mass. (See the videos on special relativity).