Answer: If the light ray hits the boundary at an angle which is not perpendicular to or parallel to the surface, then it will change direction and appear to `bend'
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First identify which is being oxidized and reduced. In this case, the Mg is being oxidized and the Hg is being reduced.
Mg --> Mg+2
<span>Hg+2 --> Hg+1
</span>
Then you have to balance each half reaction first with electrons before adding them together in one equation

⇒

and

⇒
and then combine them together to form

⇒

It isn't necessary to keep the electrons but its essential to know how many there are in order to know how many are in the equation in order to calculate the reaction energy. Note: A<span>dd H+ and H2O to balance the H's and O's in acidic solution if needed.</span>
A circuit with many paths for the current to travel through and not simply one is classified as a parallel circuit. Here the circuit can have many loops of resistors or light bulbs that can be attached.