Iron
How does the electric potential energy between two charged particles change
if one particle's charge is reduced by a factor of 3?

in this image, you can see solar radiation going through ocean water.

no image, but probably absorption

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg

3. dark matter

empty space could also be a simple vacuum