Answer: B. Nodes
Explanation:
Standing waves (so called because they seem to be immobile) occur when two waves interfere with the same frequency, amplitude but with different direction, along a line with a phase difference of half wavelength.
In these waves there are two types of points:
The <u>nodes</u>, which are points that remain motionless or stationary and do not vibrate. They are <u>due to the destructive interference of both waves when they meet. </u>
The antinodes, which are points that vibrate with a maximum vibration amplitude. They are <u>due to the non-destructive interference of both waves</u>.
Answer:
4.6 years
Explanation:
This is solved using Kepler's third law which says:

Where
T = Orbital period of the planet (in seconds)
a = Distance from the star (in meters)
G = Gravitational constant
M = Mass of the parent star (in kg)
From the information given



We put this into Kepler's law and get:

This when converted to years is 4.6 years.
What gas? Gas is an invisible form so I don't see how it would have a "defined structure".
Answer:
Germanium
Explanation:
Germanium is a chemical element that is grayish white metalliod
<span>The correct option is C. Energy cannot be created or destroyed. This statement is known as law of conservation of energy, and it implies that whenever a certain form of energy does change, the loss of this form of energy must have converted into an another type of energy. A typical example is an object falling to the ground: initially, the object has gravitational potential energy. As the object falls down, it loses potential energy (since its altitude from the grounf decreases), but it acquires kinetic energy (because its velocity increases). In this example, potential energy has converted into kinetic energy, but the total energy of the object has remained constant.</span>