Quantum 101 Episode 8: Photoelectric Effect Explained

Digital cameras, small enough to be embedded in our phones, have transformed photography and changed how we interact with the world and each other.

But did you know that this sophisticated piece of modern technology has its roots in the science that won Einstein a Nobel Prize?

Most smartphones today use a sensor called a complementary metal oxide semiconductor or CMOS. It's similar to a CCD or charge coupled device and works because of this one weird trick physicist discovered more than a century ago.

This video discusses how quantum mechanics, once an esoteric flight of fancy, now plays a role everywhere we look.

Join Katie Mack, Perimeter Institute’s Hawking Chair in Cosmology and Science Communication, over 10 short forays into the weird, wonderful world of quantum science. Episodes are published weekly, subscribe to our channel so you don’t miss an update.

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[mimidhof]

Wonderfull series, I want more please keep going on.

[cubeow]

Best YouTube video explaining this effect

[alpbaharcan]

Thank you for these episodes. Inspiring

[WingZeroSymphonics]

Gosh, Eisntein was awesome. It reminds me of how sometimes there are people who discover things that other people can’t comprehend. Until this day, humanity is still catching up with Einstein’s work.

Yes. I wonder what analogies can be made with human observation, storing and projecting of info and that of a camera. And whether the human mechanism can gather from such analogies for a more effective processing mechanism. May be useful in the realm of psychology or neuroscience.

[Roberto-REME]

Excellent video, Katie and great explanation of the photoelectric effect. I liked Damian's contribution as well, but I must say it was not Einstein who 1st thought of photons not just as waves but as physical packets. If I remember correctly it was Newton. First, Newton = light is made of small particles. 2nd: Thomas Young (1801) = light is a wave. 3rd. Einstein = light is quantized, but it's both a particle and a wave. Thank you for a great vide Katie and I wished you would do one on gravity not a force and the whole business of "...it's not pulling you down, rather the earth is rising." Love to hear your explanation of this phenomenon.

[TheScentofmusic]

Such a nice and in an enthusiastic way of presentation. Such should be the presentations on explanations.

[philo]

Thank you so much! Best video I have ever seen for the photo electric effect. Keep keep them coming.

[jacksourlis]

1. The apparent paradox that arises when trying to reconcile the wave function perspective with Einstein's well-established photoelectric effect theory.
2. The possibility that the wave function may simply not be a relevant or necessary consideration in explaining the photoelectric effect, which operates solely on the frequency-based principles.
3. How this could lend support to the MWI's assertion that the wave function does not actually collapse, since the wave function seems unnecessary for understanding a fundamental quantum phenomenon like the photoelectric effect.
4. The importance of critically examining the scope and limitations of the wave function concept, rather than automatically assuming its applicability to all quantum mechanical processes.

[sampleoffers]

Great video but now I have to search if semi conductors can convert the light into electricity passively without the phone battery factoring and if ultra violet is a frequency itself without needing to be light specifically...and then if thermal energy can be converted into ultra violet light with a filter or semiconductor...This info obviously all fascinating itself though.

[stevenverrall]

Both electrons and photons are quantum fields describable by probabilistic wavefunctions. They are neither particles nor waves, but possess properties of both particles and waves.

[HsanEener-vjvx]

What type of light emits from chalk? I know this is a silly question but when you have two metals and drop one on the other why do we only hear one sound? Why don't we hear both metals? Are we acclimated to the sound or is it on a bend ?
Is it because of concave?

[helicalactual]

Light is like water. Quantize the water by creating the smallest possible surface area for h2o, then the drops act as classical, the ocean acts as waves.
That resolves your paradox.

[adriangheorghe]

The photoelectric effect is produced by the electric impulse that appears, through electromagnetic induction, upon the sudden damping of the high-amplitude standing wave, formed upon the incident of the photon in the metal, through the constructive interference of all the component waves of the wave packet of the incident photon, after contraction and refraction them at 360 degrees.
In the case of the Compton Effect, the high-energy gamma photon that enters the atom contracts longitudinally 137 times and transversely 4 times and splits into two high-energy bipolar standing waves, one rotating around the nucleus and the other around the electron in the deep layer. In this way, gamma photons of lower frequency and energy than the incident gamma photon would be born. Stationary waves, of high amplitude, behave like an elementary charge in the spiral. When the standing wave breaks, through electro-magnetic induction, a high-power electric impulse would appear, which accelerates the electron in the immediate vicinity and transmits a recoil to the nucleus, which releases the photon from the circum-nuclear standing wave.

[lynoskitchen]

Does photoelectric effect relates to the momentum of the light caused by magnetic field?or just only the effect of photons?my brain is mixed😂

[leopardtiger]

If electrons are knocked out of metal plate the metal plate should get positively charged. Electrons are not knocked out it is but more complex.

[twentytwan]

Is photo electric effect the same as an ionization of an atom? They both knock out electrons out of an atom

[DavidGreen-ns]

I still get mad when a machine won't accept my quarters😮

[NoseyNick]

Does she mean CMOS Sensors when she says see-mo sensors? Or something else?

[peteasher]

im 14 i learned quantum physics for fun

[antiHUMANDesigns]

I thought he introduced photons as a means to solve the ultraviolet catastrophe?