Answer: B) The fireworks give off heat
In the context of chemistry, yes. Energy input is always equal to the energy output.
The reflection from plane mirror is shown in the diagram.
<h3><u>Explanation</u>:</h3>
The mirror is a plane surface which can reflect light. The diagram attached shows the schematic representation of reflection that occurs in a plane mirror.
The laws of reflection states that the incident ray, reflected ray and the normal at the point of incidence lies at the same plane. Here we can also see that all are lying on a same plane.
The second law states that angle of incidence is equal to angle of reflection. Here we can also see that the i =r. It is applicable here too.
Non-valence electrons: 1s22s22p6. Therefore, we write the electron configuration for Na: 1s22s22p63s1. What is the highest principal quantum number that you see in sodium's electron configuration? It's n = 3, so all electrons with n = 3 are valence electrons, and all electrons with n < 3 are non-valence electrons.
To work this out you do 400÷20=20