Surface tension - My definition -
It's exactly what it says - The tension of a surface with a liquid (such as water), caused by the attraction of the surfaces layer ---- I hope this helps ---- I actually did research it and got some of this from a dictionary, but I changed some of it, too.... Sorry if this doesn't help :)
Answer: Negative
Explanation:
An oxygen atom has the chemical symbol O. Its atomic number is 8, with an electronic configuration of 1s2, 2s2 2p4.
Now, due to the incompletely filled p-orbital, oxygen picks up two additional, free-floating electrons (2e-) to complete its outermost shell. And since each electrons received carries a negative charge, oxygen atom becomes a negatively charged divalent ion, O2-
See the equation below
O + 2e- ---> O2-
Answer:


Explanation:
Wave 1, 
Wave 2, 
Wave 3, 
Wave 4, 
The general equation of travelling wave is given by :

The value of
will remain the same if we take phase difference into account.
For first wave,



For second wave,



For the third wave,



For the fourth wave,



It is clear from above calculations that waves 1 and 3 have same time period. Also, wave 2 and 4 have same time period. Hence, this is the required solution.
Okay, haven't done physics in years, let's see if I remember this.
So Coulomb's Law states that

so if we double the charge on

and double the distance to

we plug these into the equation to find
<span>

</span>
So we see the new force is exactly 1/2 of the old force so your answer should be

if I can remember my physics correctly.