There are 3 lessons in this physics tutorial covering The Photoelectric Effect. The tutorial starts with an introduction to The Photoelectric Effect and is then followed with a list of the separate lessons, the tutorial is designed to be read in order but you can skip to a specific lesson or return to recover a specific physics lesson as required to build your physics knowledge of The Photoelectric Effect. you can access all the lessons from this tutorial below.
In this Physics tutorial, you will learn:
Can you make a 20 kg object move along a flat horizontal surface by pushing it by a 100 N constant force if the friction coefficient is 0.4?
What happens if you use the same force but in this case, you split it into 5 attempts of 20 N constant force each?
Ten people are behind a 2 m high wall. Can they climb over the wall?
What if there are more people but the wall is also higher? For example, if there are five times more people and the wall is five times higher, can anyone climb over the wall without any aiding tool? What if there were ten thousand people behind a 10 m high wall? (Recall what happens in prisons to answer this question).
Obviously, in all the above examples, we referred to situations that apparently are similar, but which have fundamental differences in the outcome. Thus, a 100 N force can move the 20 kg object if the friction coefficient is 0.4 as based on the Newton's Second Law of Motion we have
This means the object accelerates at
This cannot occur when we apply 5 times a 20 N force as Fnet is negative (Fnet = 20 N - 80 N = - 60 N). Hence, since the object is initially at rest, it cannot decelerate further, so it cannot move.
The example regarding people climbing over the wall is more evident. If the wall is 2 m high, all people can climb it over as one of them can carry the other people on its shoulders and so on. But if the wall is 10 m high, none of them can climb it over, even if there are thousands of people behind the wall. That's why people cannot escape from prisons.
The above examples are given purposely, to demonstrate that some phenomena do not work equally when split into smaller pieces. In the previous tutorial, we saw that light is discrete, as it is made by a large number of small "sparks" known as photons. Now, we will see what happens when a prolonged weak light falls on a metal surface and then we will compare the outcome to another case, where a strong light falls on the same metal surface. The, we will explain the phenomenon observed.
Please select a specific "The Photoelectric Effect" lesson from the table below, review the video tutorial, print the revision notes or use the practice question to improve your knowledge of this physics topic.
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