Please help me with this physics question

[yimfong]

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In the following circuit diagram, 5 identical electrical appliances rating "125W, 5V" are connected with the secondary coil of a 10:1 step down transformer. The current flowing through the primary coil of the transformer is 0.4A. Assume that there is no resistance in the coil.
Q: What is the efficiency of the transformer?

I will be highly grateful if u can show ur steps and explainations to me because the efficiency i got is over 100%!
Thanks!

 

[klinzou]

This being an ideal transformer?

 

[yimfong]

Must not be since the question requires you to calculate the efficiency,

 

[india7]

I don't know how much I can help on the actual question but check out examkrackers.com They are an MCAT review service but have some great help with physics/all premed classes. Their physics review book is really helpful, explains things in a good, clear language.