Voltage transformations (1 Viewer)

[mystify]

"Explain why voltage transformations are related to conservation of energy"

I had this in a trial paper and got 1/3 marks but cant understand how/why. The following is my answer....if im on the wrong track in any way i hope someone can lead me in the right direction. Thanks for any input


The law of conservation of energy states that energy cannot be created nor destroyed but can be changed from one form to another. In a transformer, the voltage is not created but induced in the secondary coil by the change in flux of the magnetic field in the primary coil. Hence the power input must be equal to or greater than the power output in the secondary coil. Since we cannot get a larger output from the secondary coil there must be some sort of trade off when we step up a voltage or step it down. This trade off occurs with the current: increase in voltage=decrease in current and vice versa.

 

[gordo]

p=vi
joules per second = voltage . current
since conservation of energy exists, if u change the current, the voltage will change, not the power. (also seen in v=ir)
hence voltage transformations are possible by changing current because the conservation of energy law exists

 

[peeasoup]

hahaha
I got 3 marks for saying that in a step up transformer, the voltage is increased in the secondary coil, but the current is reduced to maintain the energy constant, and stating LCE.

 

[t-i-m-m-y]

P1 >= P2

therefore;

V1I1 >= V2I2

equality holds for 100% effeciency.

using the word 'tradeoff' in your answer seems rather dodgy to me. don't ask why. use some mathematical expressions in your answer. 'tis so much easier

 

[The Bograt]

Also show the consequences if the Law of Conservation of Energy did not apply - ie the world would go to buggery

 

[ashtor]

man your answer seems good enuf to me...its exactly what Jacaranda has

 

[d_elmo]

it is related to the conservation of energy as in an ideal transformer,

power in=power out.