That's related to the First Law of Thermodynamics - the Law of Conservation of Energy.
First law
The first law of thermodynamics states that whenever energy is converted from one form to another, the total quantity of energy remains the same.
There are many different types of energy; the details of energy conversion are different, from case to case.
No, it won't increase nor decrease. Energy can't be created or destroyed (First Law of Thermodynamics). On the other hand, the amount of USEFUL energy will usually decrease in energy transformations (Second Law of Thermodynamics).
... and converted from one form to another.
It is not converted, it's naturally changed from one form to another.
Since energy can't be created nor destroyed (First Law of Thermodynamics), a loss or waste of energy really means that useful energy is converted into unusable energy (Second Law of Thermodynamics).
That is known as "conservation of energy"; also as the "first law of thermodynamics".
That's the "Conservation of Energy"; also know as the "First Law of Thermodynamics". Please note that while TOTAL energy is conserved (doesn't change), in most or all processes that occur in practice, USEFUL energy is converted into UNUSABLE energy - often heat.
Usually yes. The energy isn't entirel "lost" - in the sense of the First Law of Thermodynamics it is still there. However (in the sense of the Second Law of Thermodynamics) it gets converted to a lower-quality energy, that can no longer be used, so for all practical purposes it is lost.
The closest law is the Second Law of Thermodynamics. Note that not necessarily "most" energy will be converted to unusable heat, but it is almost inevitable that some will.
You must be referring to the two Laws of Thermodynamics. Stated in terms of energy: 1. The First Law of Thermodynamics is the Law of Conservation of Energy, meaning that energy can not be created or destroyed. 2. However, useful energy is continuously being converted into unusable energy. This is irreversible. This is the Second Law of Thermodynamics.
First Law of Thermodynamics: Energy can be converted from one form to another, but cannot be created or destroyed.Second Law of Thermodynamics: The second law of thermodynamics states that for any process occurring in a closed system, the entropy increases for an irreversible system and remains constant for a reversible system, but never decreases.