Which rule for assigning oxidation numbers is correct
Hydrogen is usually -1.
Oxygen is usually -2.
Apure group 1 element is +1.
Amonatomic ion is 0.

B.

Explanation:

Oxygen is really -2

While the other options in correct form is

Hydrogen O.S is +1

A pure group 1 element is 0.

And

A monoatomic ion's O.S is the charge contained by it

convex lenses are thicker at the middle. rays of light that pass through the lens are brought closer together (they converge). a convex lens is a converging lens. when parallel rays of light pass through a convex lens the refracted rays converge at one point called the principal focus.

answer; equivalent to a one(1) horsepower motor;