<span>Unexpected orbital velocities of stars around the centers of galaxies led astronomers to predict the existence of dark matter. Dark matters are hypothetical substance that are believed to account for around five-sixths of the matter in the universe.</span>
We Know: MA = d₁ / d₂
Here, d₁ = 4
d₂ = 10-4 = 6
Substitute their values into the expression:
MA = 4/6
MA = 2/3
So, Your Answer would be 2/3
Hope this helps!
Answer:
I. a, c, f and h
II. e
III. b, d, g and i
IV. i
Explanation:
I. Chemical symbols are simple abbreviations used to represent various elements or compound. They consist entire of alphabet.
For the diagram given above, the labelled parts which represent chemical symbol are: a, c, f and h
II. Coefficients are numbers written before the chemical symbol of elements or compound.
For the diagram given above, the labelled part which represent Coefficient is: e
III. Number of atoms of element present in a compound is simply obtained by taking note of the numbers written as subscript in the chemical formula of the compound.
For the diagram given above, the labelled part which represent the number of atoms of the element are: b, d, g and i
IV. When no number is written as subscript in the formula of the element in the compound, it means the element has just 1 atom in the compound.
For the diagram given above, the labelled part which indicates that only 1 atom of the element is present is: i
The phonograph was invented for people with hearing problems. Option D is correct.
<h3>
What is a Phonograph?</h3>
- It is a device that records sounds or music in the grooves of a plate and plays them.
- This was the first invention that can record and play music.
- It was invented by Thomas Alva Edison.
- This device helps people with hearing problems by allowing them to practice concentrating on a different sound.
Therefore, the phonograph was invented for people with hearing problems.
Learn more about Phonograph:
brainly.com/question/858851
Coulomb's Law: The interaction between charged objects is a non-contact force that acts over some distance of separation.
