<h2>Answer:</h2><h2> b hopefully this helps you with work </h2>
Answer:
Doppler Theory
Explanation:
it's a theory regarding the change in wave frequency during the relative motion between a wave source and its observer.
This problem uses the relationships among current
I, current density
J, and drift speed
vd. We are given the total of electrons that pass through the wire in
t = 3s and the area
A, so we use the following equation to to find
vd, from
J and the known electron density
n,
so:

<span>The current
I is any motion of charge from one region to another, so this is given by:
</span>

The magnitude of the current density is:

Being:

<span>
Finally, for the drift velocity magnitude vd, we find:
</span>
Notice: The current I is very high for this wire. The given values of the variables are a little bit odd
Answer:
C.) To indicate different versions of the same variable.
Explanation:
Variables in physics often include a subscript. These subscripts are used for indicating different versions of the same variable in physics.
Basically, subscripts are used to represent the beginning (initial) and ending (final) position or point of a variable in physics.
For example, we would look at Gay Lussac' Law of gases.
Gay Lussac law states that when the volume of an ideal gas is kept constant, the pressure of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Gay Lussac's law is given by;


Where;
represents the initial temperature.
represents the initial temperature.
represents the initial pressure.
represents the initial pressure.
Note: 1 and 2 are the subscript while T and P are the variables.