13. true or false: "converting one form of energy into another form
always involves a loss of useable energy.
plz

It’s true, and there are lots of examples for it.
Take a speaker that has to convert electrical energy to sound energy. Note, that while the speaker is playing, it also vibrates. This is because the speaker has not been able to convert 100% of the electrical energy into sound, but has been turned, as an unwanted by-product, of course, into kinetic energy.
Another example would be a car engine, converting chemical energy into kinetic. Note that the car heats up, as well as makes a very large ruckus. This, obviously by now, is because the fuel has not been completely converted into kinetic, but also sound and heat.