(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

The specifications of a transformer for a small appliance read "Input: 110 V, 6.4 W" and "Output: 8.9 V, 270 mA". What is the efficiency of this transformer?

2. Relevant equations

P = I * V

V = I * R

3. The attempt at a solution

6.4 W / (8.9*(270*.001)) ---> I think this is wrong

I am just not sure how the voltage drop of the transformer would affect the power output...

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# Homework Help: Efficiency of a Transformer

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