Answer:
The value is 
Explanation:
From the question we are told that
The speed of in a vacuum is 
The speed of light in the material is 
Generally the reflection of the material is mathematically represented as

=> 
=> 
Answer:
y=8
Explanation:
every time you multiply x by 3 you divide y by 3.
x=2, multiply it by 3: x=6
y=24, divide it by 3: y=8
With the increase in the temperature of the star, the brightness of the stars will also increase.
<u>Explanation:</u>
The brightness and surface temperature of stars ordinarily increment with age. A star stays close to its underlying situation on the fundamental arrangement until a lot of hydrogen in the center has been devoured, at that point starts to advance into a progressively brilliant star.
The brightness of a star relies upon its structure and how far it is from the planet. Space experts characterize star brilliance as far as clear extent — how splendid the star shows up from Earth — and outright greatness — how brilliant the star shows up at a standard separation
The answer is C because the three metals that are magnetic are iron, nickel, and cobalt, and it is metal so it is a conductor of electricity.