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Light Intensity

Posted: Sat Oct 12, 2019 2:44 pm
by ngarcia
Just to clarify, increasing light intensity increases the number of photons. And, if, and only if, the energy per photon is greater/equal to the energy needed to remove an electron, then increasing light intensity results in more ejected electrons. However, one cannot assume that electrons are being emitted with high intensity light alone. Do I have a correct understanding?

Re: Light Intensity

Posted: Sat Oct 12, 2019 2:57 pm
by Ronak Naik
Yes, that is exactly correct. The intensity of light is directly related to the number of photons not the common mistake of thinking about energy. Once enough energy from the photon has been put in, the electron will be ejected with a kinetic energy of 1/2mv^2. Each photon will eject one electron if the photon has greater energy than the required work energy.

Re: Light Intensity

Posted: Sat Oct 12, 2019 3:12 pm
by Amanda Ung 4D
Sounds good! Remember to consider light as photons, or packets of energy where one photon interacts with one electron. High intensity light with long wavelengths and low frequency wouldn't be able to eject electrons; therefore, it really depends on the energy of the photon and not the intensity of the light. That is what I took from the lecture.

Re: Light Intensity

Posted: Sat Oct 12, 2019 3:55 pm
by chari_maya 3B
One thinking point in the texbook asked why ultraviolet radiation is much more harmful to living tissue than infared radiation... I was wondnerinf if someone could explain the answer.

Re: Light Intensity

Posted: Sat Oct 12, 2019 4:22 pm
by Alexandra Bartolome 2H
chari_maya 3B wrote:One thinking point in the texbook asked why ultraviolet radiation is much more harmful to living tissue than infared radiation... I was wondnerinf if someone could explain the answer.


I think this is because ultraviolet radiation has higher frequency and shorter wavelengths than infrared radiation, which means it has more energy to penetrate our skin and do damage.

Re: Light Intensity

Posted: Sat Oct 12, 2019 4:34 pm
by faithkim1L
Yes, this is correct. The light intensity is directly related to the number of photons.

Re: Light Intensity

Posted: Sat Oct 12, 2019 4:39 pm
by Arianna Perea 3H
How come the photons dont have enough energy with low frequency lights?