The principle of work states that the ratio of work output to work input is always

work output is always less than work input - the ratio is less than 1.

Explanation:

This principle comes from the fact that a machine or system cannot produce more work than is supplied to it, because this would violate the energy conservation law (work is a type of mechanical energy).

In theoretical machines called "ideal machines" the input work is the same as the output work, but these machines are only theoretical because in real applications there is always some type of energy loss, either in heat produced by a machine or processes for its operation, for this reason the output work is always less than the input work.

Regarding the ratio work output to work input:

because work input WI is always greater than work output WO.

second mirror gathers light from a faraway object and reflects it to another mirror. - a.

i think it would be 5