Because upward buoyant force is slightly higher than gravitation force for this particular object
A reversible change is a change that can be undone or reversed
Answer:
Density of 18.0-karat gold mixture is
.
Explanation:
A mixture of 18 parts gold, 5 parts silver, and 1 part copper.
Let mass of gold be 18x
Let the mass of silver be 5x
Let the mass of copper be 1x
The density of gold = 
The density of silver = 
The density of copper =

Volume of the gold in the mixture = 
Volume of the silver in the mixture = 
Volume of the copper in the mixture = 
Mass of the mixture = M = 18x+5x+1x =24x
Volume of the mixture = 
Density of the mixture:

Choice-a is a very rubbery, imprecise, ambiguous, slippery statement. But it's probably less wrong than any of the other choices on the list.
Answer:
C
Explanation:
When A and B come in contact with each other, +12 - 12 = 0 so their changes cancel.
Now C has a charge of +12
When A and C come together they each have an equal share of that 12, so each of them has 6
So the answer is
A B C
6 0 6
which is C