Which statement best expresses energy conservation in a general transformation?

• A. Energy is created during a transformation.
• B. Energy disappears after transformation.
• C. The total input energy equals the sum of all outputs in all forms.
• D. Energy is not conserved in most processes.

Answer: (C)

Energy conservation is the idea that energy can change its form but the total amount stays the same. In any transformation, the energy you start with can appear as different outputs—light, sound, motion, heat, chemical energy, etc.—and if you add up all those outputs, you get the same total energy that you put in. A simple example is a lightbulb: electrical energy becomes both light and heat. When you sum the light energy and the thermal energy, it matches the electrical energy supplied. This shows why energy isn’t created or destroyed during a process; it’s just redistributed among different forms. The notion that energy isn’t conserved in most processes isn’t accurate—the conservation holds broadly, as long as you account for all energy forms, even the energy that escapes as heat to the surroundings.