Arake is held so that its input arm is 0.4 meters and its output arm is 1.0 meters. what is the mechanical
advantage of the rake?

You're holding it above the middle, so the MA is less than 1 .

It's  0.4/1.0 = 0.4

The modern-day generator works on the principle of electromagnetic induction discovered by michael faraday in 1831-32. faraday discovered that the above flow of electric charges could be induced by moving an electrical conductor, such as a wire that contains electric charges, in a magnetic field.