Does frequency of light affect the current of the Photoelectric Effect?

This week, one of my students challenged my understanding of the photoelectric effect… Basically, he didn’t think that the current produced by the photoelectric effect should be affected by the frequency of the photons, but only by the intensity of the light. After a while, he convinced me – more photons per second (the intensity) should mean more electrons per second, but why would the speed of the electrons have an effect on the current?

However, from the PHET simulation of the photoelectric effect as well as the experimental results of a photoelectric device we have at school, it was obvious that current should be affected by frequency. I looked on the internet for a possible explanation… I couldn’t find anything reasonable. I even looked at the spectrum of our light used in the experiment, thinking that the intensity of the blue light was larger than the intensity of the red light – but no, that wasn’t the case.

So I asked an expert – Dr. Friesen, the professor responsible for the Modern Physics course at the University of Calgary. He was kind enough to reply with an incredibly clear explanation.

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Importance of using students’ names in class

When I tutor students, I get to know them quite a bit better than the ones I teach as part of a class. They open up to me about anything and everything, and sometimes this lets me understand them better. I learn from them, just by listening. A thing that came up during one of my tutoring sessions (with a girl named Erin) was the use of names. She was complaining that one of her teachers only used terms of endearment to her students, instead of their proper names. So instead of calling her Erin, she would say: “Sweetheart”, or “Dear”. Even though this was of the only complaint (that she could really verbalize) about her teacher, Erin could honestly say that she didn’t like her teacher. Why is it that this seemingly small thing bothered her so much?

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Does a bottle filled with water or snow roll down a hill faster?

One jar filled with water, the other filled with snow… which one will roll down faster?

Question: Does a bottle filled with water or snow roll down a hill faster?

Prediction? Take your time. Think about it. Ask your friends, ask your kids, ask your parents.

Make sure to get explanations from yourself and all the people you ask, not just guesses.

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Textbooks – what is their purpose in our classroom?

In Canadian schools textbooks are usually large, hard cover, with glossy paper, filled with beautiful pictures, drawings, many “interesting factoids”, spanning a large amount of information. With these gorgeous books, the publishers and authors think that the books are devoured by our students, and that the students read them everyday expanding their mind. I don’t think this is really the case. There are many disadvantages to these textbooks

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