Spheres representing nitrogen and oxyfgen are different colors so you can easily tell them apart.
There is no correct description on that list of choices.
Answer:
- The diameter of the molecule of oil is

Explanation:
We define density as

So, the volume for our oil will be




the volume for a cylinder with radius r and height h is

So, we can obtain the height of the droplet of oil as:

the radius is


And this is the diameter of the oil molecule.
Answer:
Electrons.
Explanation:
Electricity was discovered before the discovery of electrons by J.J Thompson in 1896. Before the electron, it was thought that it is the positive ions that move through the wire and carry current—that's why today the conventional current represents the flow of positive charges.
After J.J Thompson's discovery of the electrons, it was realized that it is the electrons that actually carry the current through the conductor. But changing the direction of the conventional current didn't seem appropriate, and that's why the convention continues to be used to this day—reminding us that once it were the positive ions that were thought to carry the current.
Answer:
<em>Yes, they are moving in opposite direction one to the other.</em>
Explanation:
Velocity is a vector quantity, which means that it has both magnitude and direction. The magnitude shows the size of the velocity, and the direction shows which way it is moving in reference to a chosen reference direction. If the red box is assigned a positive velocity, and the blue box is assigned a negative velocity, as indicated in the question, then it means that the red box, and the blue box, both move in opposite direction to the other.