In every energy change...?

Question

a. overall efficiency is reduced

b. heat is lost

c. some usefulness is lost

d. some energy is wasted

e. all of these

I answered this question and got it wrong, i answered d. What is the correct answer, would it be e?

Answer 1

Since answers a through d are generally true for every energy change,  I'd have to go with e. They're all just different ways of describing the inefficiencies encountered in performing energy conversions.

Whether you term it 'energy' or 'usefulness', the meaning is the same. Whether you use the term ' lost' or 'wasted', again, the intent is the same.  

Answer 2

yup,b and d are certainly same ;heat is a kinda energy .it must be e then

Answer 3

Since b,c,and d are basically all saying the same thing just in different ways.

the obvious answer would be e.