3780 km.
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Answer:D.Refractive Indez
Explanation:
It is usually expressed the other way: the ratio of the speed of light in a vacuum to the speed of light in a medium. In that case, it is called the "index of refraction".
Answer:

<em>The potential environmental impacts associated with solar power—land use and habitat loss, water use, and the use of hazardous materials in manufacturing—can vary greatly depending on the technology, which includes two broad categories: photovoltaic (PV) solar cells or concentrating solar thermal plants (CSP).</em>
Explanation:
I just answer the second question
Gravitational potential energy<span> is </span>energy<span> an object possesses because of its position in a </span>gravitational<span> field. </span><span>The equation for </span>gravitational potential energy<span> is GPE = mgh.
GPE = 1200(1.6)(350) = 672000 J
Hope this answers the question. Have a nice day.</span>
Answer:
The Earth's magnetism is generated in the core, which is composed of iron that is constantly churning
Explanation:
Magnetic fields are produced by charges in motion, therefore by currents.
The outer core of the Earth consists mainly of melted iron that is in constant motion. This iron in motion actually acts as a giant current, and therefore it is responsible for the creation of the Earth's magnetic field.
The magnetic field of the Earth is very weak, in fact its magnitude is on average between 25 and 65 microtesla (for comparison, normal magnets can even produce magnetic fields of a few millitesla).
However, its role is very important for the Earth: in fact, it provides a shield that blocks most of the harmful radiation coming from the Sun.