Just subtract the both of them.
1. The vertical columns on the periodic table are called groups or families because of their similar chemical behavior.
2. All the members of a family of elements have the same number of valence electrons and similar chemical properties.
3. The horizontal rows on the periodic table are called periods.
Answer:
n = 1.5
Explanation:
The speed of light in vacuum is 300000000 m/s
The speed of light in glass is 200000000 m/s
We need to find the refractive index of the glass.
We know that, the ratio of speed of light in vacuum to the speed of light in medium is equal to refractive index of the medium.

So, the refractive index of the glass is 1.5.
█ Answer <span>█
</span><span>The energy from our sun is produced by fusion of hydrogen.
Choice D is the answer.
</span><span>Hope that helps! ★ If you have further questions about this question or need more help, feel free to comment below or leave me a PM. -UnicornFudge aka Nadia
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