Final answer:
Heat transferred into a system changes its internal energy, which can manifest as a temperature increase or a state change, and can also be converted into potential energy or do work.
This energy can be recovered later, as illustrated by lifting objects, like during pyramid construction.
So, Correct option is; a) Yes, energy is stored as heat.
Step-by-step explanation:
When heat transfers into a system, the energy is not stored as heat. Instead, it may be converted into internal energy which can increase the temperature of the system or change its state, or it could be converted into work or potential energy depending on the process.
If heat is added to a system, such as immersing metal in hot water or bending a wire, the internal energy of the system increases, and this is often reflected in an increase in its temperature. Conversely, energy is transferred out of a system when it loses heat or when the system does work on its surroundings.
For example, the energy used to lift stone blocks during the construction of the pyramids is stored within the stone-Earth system as potential energy that could do work in the future.
Similarly, when a person does work on a briefcase to carry it up stairs, the system (briefcase-Earth) stores the energy, and it can be recovered later.
However, when a lawn mower is pushed at a constant speed, the energy input by the person pushing is removed continuously by friction and eventually leaves the system as heat transfer.