how do we know that some energy is lost in energy conversions?
369832
Energy is not "lost" it is converted to a form that cannot be used.\n\nDrop a ball from a certain height and the ball does not bounce back to the original height...that is because some of the energy was converted to sound (you hear the ball hitting the floor)...some was converted to heat (the ball and the spot on the floor where it hit are just a teeny bit warmer)\n\nFor the most part you can observe this "lost" energy (usually they are in the form of heat, light or sound)
468574
The conservation of energy rule in physics dictates that energy is always conserved, so it can't be destroyed merely changed to another type. Perhaps an example could be in a crash, the kinetic energy is turned into sound and heat energy primarily, but the energy still exists.
511885
Energy can take the form of heat, light, vibration, momentum or sound. It can also be stored as potential energy. Anytime you interconvert among these forms of energy, you can say it is "transferred". Chemical reactions can include some or all of these, with chemical bonds representing stored potential energy.\n\nIn nuclear reactions, you can say that energy and matter are interconverted as well.
509058
No way.  And the evidence is easy to find, too.  Plug in a power converter and run something off it for a while, then put your hand on the converter -- it's hot, right?\n\nThat heat is *wasted energy* -- converting electricity from one voltage to another requires work to be done, and that work generates heat, which is the indication of the inherent inefficiences of the process.  If you then reconvert the electricity to 120V, you will experience a second inefficiency, evidenced as more heat lost.
285189
It has been a very long time since I studied all of this in undergrad, but I believe that after impact, some of the kinetic energy is lost/tranformed due to heat or friction.
381905
According to the Law of the Conservation of Energy, energy is neither created nor destroyed; it is transferred or transformed from one form to the other in an isolated system.
390030
heat mainly - the energy is wasted in the form of heat instead of transferable energy
301288
There are very simple way of checking this type of thefts. Switch off the source it self, and check if your energy meter is still working/ revolving. If yes, it means that your doubt is correct. disconnect that load first by calling the experts of the system. and then check further.
941720
Doesn't that have something to do with Einstein's e=mc^2?  It sure looks like it.  The rest of seems to be an example of an explanation of the inefficiency of practical mass to energy conversions.  I could be wrong.\n\nOh, by the way:  what are you asking?
1156590
E = energy\nm = mass\nc^2 = speed of light squared\nMass and energy are equivalent.\nThis is a part of theory of relativity of Albert Einstein.\n\nDuring nuclear fission and fusion about 1% mass disappears and an equivalent amount of energy comes free.\n\nDuring annihilisation all mass 'changes' into energy.\nDuring creation of an electron and positron the inverse happens.
725582
Firstly, electrical energy from the wall socket is transferred to the toaster.\nThis is the converted into heat energy by the filament.\nThere will also be some wasted heat and light energy.\nFinally, the spring will store spring potential energy when it is down, converted to kinetic energy as it rises, with a piece of toast hopefully!
41255
When you say waste in terms of energy you normally mean energy being turned into a non-useful form, which is almost always heat. So while for the system energy is conserved, it appears that energy is being 'wasted'.
15241
Well yes and no. According the the principal of conservation of energy there is a set amount of energy and it can only be converted, not created or destroyed. But as we look into more complicated realms of physics, we understand that matter can be converted  into energy, and vice-versa.
953904
No common denominator for the energy in the things you mention except that if it has mass, then it embodies the energy given in E = mc^2\n\nThis applies to ALL matter.
644089
You may be familiar with two laws that are based on experimental results: \n\nLaw of Conservation of Matter states that the mass of a chemically reacting system remains constant. \n\nLaw of Conservation of Energy (also known as the first law of thermodynamics) states that energy may be transformed from one form into another, but it cannot be created or destroyed. Consequently, the total amount of energy in the universe never changes. \n\nHowever, these laws are in fact identical¼\nMatter and energy are interconvertible. The equivalence of mass and energy escaped our attention for only one reason: The change in mass accompanying the emission or absorption of heat in non-nuclear reactions is so small that it is undetectable. \n\nIn any exothermic reaction, matter is converted into energy; conversely, in any endothermic reaction, the energy absorbed is converted into matter. \n\nWe have not been educated to express energy in mass units. We therefore use a conversion factor to change the mass unit (kg) to the energy unit (J). \n\nThe interconvertibility of matter and energy was predicted by Albert Einstein in 1905. It is described by the equation: \n\nDE = Dmc2\n\nwhere DE is the energy change in joules when Dm, the quantity of matter converted, is in kilograms, and the constant c, the speed of light, is in ms-1 (2.998 x 108 ms-1). The square of the speed of light is used as the conversion factor between quantities that were assumed to be dissimilar\n\n\nFor more info follow the link below
1154605
None, but the transfer of energy is more correct.
25598
The energy isn't destroyed, but it is reorganized into different forms.  Think of it this way: Imagine you have a bunch of fridge magnets with words on them, and you arrange them into a brilliant poem.  When you come back later, someone else has rearranged the magnets.  All of the magnets have been "conserved"-- they're still there, and they're just as magnetty as ever-- but the particular shape that they were in when they were your brilliant poem is unrecoverable.  Sorry. <3