A step-down transformer has an initial efficiency of 80.0%. When connected to a high-voltage supply, it delivers 120 W of electrical power to a resistive load. The energy losses in the transformer are due entirely to resistive heating in the copper windings (copper losses) and eddy currents in the iron core (core losses), which are in the ratio 2:1 2:1\,2:1 respectively.
The transformer is redesigned with a laminated core, which reduces the eddy current losses by 90.0% while the winding losses and the power delivered to the load remain unchanged.
What is the new efficiency of the transformer?
85.1%85.1\%85.1%
86.0%86.0\%86.0%
90.9%90.9\%90.9%
97.6%97.6\%97.6%