Answer:
Dark matter is nonluminous material that is postulated to exist in space and that could any of Several form including weakly interacting particles.
Explanation:
dark matter is basically composed of particles that do not absorb, reflect or emit light, so they can't be detected by observing electromagnetic radiation.
The name of Pb(NO3)2 of is Lead II trioxonitrate V
The bond which exist in is Lead II trioxonitrate V ( Pb(NO3)2 ) are both ionic and covalent bond
<h3>What is a compound?</h3>
A compound is a substance which contains two or more elements chemically combined together
So therefore, the name of Pb(NO3)2 of is Lead II trioxonitrate V
Learn more about a chemical compound:
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You have a. 3, b. 2, e. 6, f. 3, i. 1
<u>Complete Question:</u>
Which of the following is not a characteristic of electromagnetic waves?
a. they can travel through a vacuum.
b. they can travel at various speeds through any one material.
c. they can be refracted.
d. they can be reflected.
<u>Correct Option:</u>
"They can travel at various speeds through any one material" is not a characteristic of electromagnetic waves.
<u>Explanation:</u>
It is a form of energy generated by interference from the oscillating magnetic and electric recorded. So we may conclude that it is created by moving electric charged particles through the vacuum so matter. This is a wave in which the two vectors vibrate each other perpendicularly and in the direction of the wave. Electromagnetic waves which involve gamma-rays, x-rays, ultraviolet rays, infrared-rays, microwaves and radio-waves can be featured by:
- They may pass through the vacuum.
- They are allowed to move through the matter and are reflectable.
- They can pass through all of the material at the same pace. This means there is still constant speed of light, which is, they can be refracted.