The correct answer is B. Calcite
Explanation:
Mohs hardness scale indicates the hardness of minerals using a scale from 1 to 10 as well as defining the objects or tools that can be used to scratch the minerals. These two features of minerals are shown in the table of the image. About this, it is shown gypsum and talc can be scratched by just a fingernail, considering minerals with a hardness of 2.5 or below can be scratched by a fingernail. In the case of calcite that has a hardness of 3, this cannot be scratched by a fingernail, but it can be scratched by a penny, which works for minerals with a hardness of 3.5 or below. Thus, the correct answer is Calcite.
Coulomb's Law: Force = k x q1x q2 divided distance square
where k=9x10^9 , q1 and q2 are the charge
So if you distance is halved, your force is stronger by 4 times
and if you distance is doubled, your force is 1/4
Ask me again if you aren't clear :)
D. It must be able to be magnetized
Explanation:
The requirement for a core to be used in an electromagnet is that it must be able to be magnetized.
An electromagnet is a type of magnet produced by electricity.
- They typically run and produce magnetic fields in the vicinity of electrical currents.
- These magnets are not permanent magnets.
- When the electrical current is removed, the magnetic property of the substance is lost.
- The core of an electromagnet is usually made up of a material that can easily be magnetized in the presence of magnetic fields.
- Some of the materials used are cobalt, iron, nickel.
learn more:
Electromagnet brainly.com/question/2191993
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Answer:
e) indicated that the speed of light is the same in all inertial reference frames.
Explanation:
In 18th century, many scientists believed that the light just like air and water needs a medium to travel. They called this medium <em>aether</em>. They believed that even the space is not empty and filled with aether.
Michelson and Morley tried to prove the presence and speed of this aether through an interference experiment in 1887. They made an interferometer in which light was emitted at various angles with respect to the supposed aether. Both along the flow and against the flow to see the difference in the speed of light. But they did not find no major difference and thus it became the first proof to disprove the theory of aether.
It thus proved that the speed of light remains same in all inertial frames.
Also, it became a base for the special theory of relativity by Einstein.
