Which observation confused scientists regarding the photoelectric effect? A. Low-intensity light does not always cause electrons
to be emitted. B. High-intensity light does not always cause electrons to be emitted. C. Low-frequency light does not always cause electrons to be emitted. D. High-frequency light does not always cause electrons to be emitted
Light does not always cause electrons to be emitted. If it doesn't, then you might think that making the light brighter would cause electrons to be emitted. That DOESN't work, but making the light higher FREQUENCY causes electrons to be emitted !
Did you catch that ? ==> If you light a match next to a piece of metal, and the match burns with a red flame and NO electrons are emitted from the metal, then you can move in with a military searchlight or a ginormous high-power laser that has the same red color and shine it on the metal, and still no electrons will be emitted. But if you light a little match next to the metal and the match burns with a BLUE flame, then electrons WILL be emitted. Knocking electrons out of the metal has nothing to do with how strong and bright the light is. It only depends on the FREQUENCY (color) of the light !
This observation was confusing until the beginning of the 20th Century, even to the smartest scientists. There was no way to explain it until 1905, when Albert Einstein pretty much invented Quantum Mechanics to explain this "Photoelectric Effect".
Of all of Einstein's great discoveries, THIS was the one for which he was awarded the Nobel Prize in Physics ... in 1922. He never won a Nobel for his theories of Relativity.
I think the correct answer from the choices listed above is option D. Solar cells convert electromagnetic energy into electrical energy. This is because the photons from the rays of light are electromagnetic waves or particles. Hope this answers the question.
