If a machine has 100% efficiency, it means that
a. output work is equal to input work.
b. output force is equal to input force.
c. output work is twice the input work.
d. output force is twice the input force.

(A).Output work is equal to input work.

Explanation:

Efficiency: Efficiency is the ability of machine.

Efficiency is the maximum of the machine that means the machine gives the maximum output with minimum input.

So we can say that,

If a machine has 100% efficiency, it means that the machine gives output equal to the input.

Hence, Output work is equal to input work.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it