Answer:
D) diffraction
Explanation:
Corona is an optical phenomenon produced by the diffraction of sunlight or moonlight, as light moves through water droplets in the atmosphere.
This phenomenon produces one or more diffuse concentric rings of light around the Sun or Moon, usually seen as colored circles.
Therefore, the explanation for these phenomena of colored concentric circles, sometimes seen with the Sun or the Moon involves diffraction.
Contact metamorphism occurs adjacent to igneous intrusions and results from high temperatures associated with the igneous intrusion. Since only a small area surrounding the intrusion is heated by the magma, metamorphism is restricted to the zone surrounding the intrusion, called a metamorphic or contact aureole
If you wrap some of the wire around the nail in one direction and some of the wire in the other direction, the magnetic fields from the different sections fight each other and cancel out, reducing the strength of your magnet.
<h2>
Resultant is 235.54 pounds at an angle 44.16° to X axis.</h2>
Explanation:
Forces are 100 pound and 150 pound and angles with x axis are 20°and 60°.
That is force 1 is 100 pound with x axis at 20°
F₁ = 100 cos 20 i + 100 sin 20 j
F₁ = 93.97 i + 34.20 j
That is force 2 is 150 pound with x axis at 60°
F₂ = 150 cos 60 i + 150 sin 60 j
F₂ = 75 i + 129.90 j
F₁ + F₂ = 93.97 i + 34.20 j + 75 i + 129.90 j
F₁ + F₂ = 168.97 i + 164.10 j

Resultant is 235.54 pounds at an angle 44.16° to X axis.