Calculating Efficiency & Energy Output - GCSE Physics | kayscience.com

A device is useful because the device can transfer energy from one useful energy store to another useful energy store.

However no device is 100% efficient. This is because the device will transfer energy to non-useful energy stores.

The energy that isn’t transferred to a useful energy store is called wasted energy, or dissipated energy. The useless energy stores are usually thermal energy stores of the surroundings.

The higher the efficiency of a device the less energy is being transferred to the useless surrounding energy stores

The equation for the efficiency of an energy transfer in terms of power is:

efficiency = useful output power transfer ÷ total input power transfer
. .

Rearrange the equation for the useful output energy transfer in terms of power is:

useful output power transfer = efficiency x total input power transfer


Rearrange the equation for the total input energy transfer in terms of power is:

total input power transfer = efficiency x useful output power transfer

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[Xusemeh]

thanks, my teacher assigned us a thing like this but didn't teach us well on how to do it

[dareenagunasekera]

This helped me so much to understand the lesson! Tysm:)

[mamadouybahbah]

So how about if the object is having a work input of 15j and an output of 9j what is the efficiency

[Cherr_yyyy]

thank you so much
your formula really helped me a lot.
this video deserves more recognition☺️

[Wekness_Spotter]

i wanted to know how to find energy output(also tell formula) when efficiency is NOT given.

[Thaimakevengu-srok]

But if the total input energy is not given?