The correct answer is letter A. 6 millimeters. <span>If an object 18 millimeters high is placed 12 millimeters from a diverging lens and the image is formed 4 millimeters in front of the lens, the height of the image is 6 millimeters.
</span>
Solution:
18 / x = 12 / 4
12x = 72
x = 6mm
Formula unit is the empirical formula of an ionic or a covalent compound. It is the chemical formula that gives the proportions of the elements present in a certain compound however it does not give the actual numbers or the arrangement of the atoms. For this case, there are 14 atoms of different elements that is involved in the compound.
The answer is, "B", "Ammonia".