Answer:
An open system.
Explanation:
An isolated system allows the exchange of neither energy nor matter with the surroundings. A closed system allows the exchange of energy, but not matter. An open system allows the exchange of both energy and matter.
Notice that in this question, light (electromagnetic wave) is a form of energy. The entry and exit of light allows this system to exchange energy with its surroundings- just as how the earth receives energy from the sun. Additionally, this system could exchange energy with its surroundings through the exchange of matter (in particular, air) with its surroundings.
Thus, the system in this question is an open system.
Using the Definition of Kinetic Energy, we have:
A frame of reference can be thought of as the state of motion of the observer of some event. For example, if you're sitting on a lawn chair watching a train travel past you ... you could even watch a glass of water sitting on a table inside the train move ... This seems like a simple and obvious example, yet when you take a step
Aluminum has 3 valence electrons.
<span>You can figure out the valence electrons by looking at its group number. Aluminum is in group 3, so it has 3 valence electrons.
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