Energy Stores and Transfers

The question asks about the Law of Conservation of Energy, which is a fundamental rule in physics that governs all energy transfers.

The law states that energy cannot be created or destroyed. It can only move between stores (e.g., chemical to kinetic) or change form. The total energy in a closed system always remains constant.

The option that says energy 'cannot be created or destroyed — it can only be transferred between stores or converted from one form to another' is the precise scientific statement of this law.

We need the correct statement of the Law of Conservation of Energy. Any option that allows energy to be created or destroyed is wrong.

The option 'Energy can be created by machines but cannot be destroyed' is incorrect — machines cannot create energy from nothing; they only transfer it between stores.

The option suggesting energy is destroyed as heat is incorrect — heat (thermal energy) is still energy. Dissipated energy spreads out but is not destroyed.

The option saying total energy decreases is incorrect — this confuses 'useful energy' decreasing with total energy, which always remains the same in a closed system.

The remaining option — 'Energy cannot be created or destroyed — it can only be transferred between stores or converted from one form to another' — is the correct statement of the law.

A rubber band is being stretched — it is deformed from its natural shape and held in that position. We need to identify which energy store corresponds to this situation.

The elastic potential energy store holds energy in objects that are stretched or compressed, such as springs, rubber bands, and elastic materials. This matches our scenario exactly.

The correct answer is the elastic potential energy store, because the rubber band is a stretched elastic material — the definition of this store.

We need to identify which energy store holds energy in a stretched rubber band that is stationary in your fingers.

The kinetic energy store requires an object to be moving. The rubber band is held still, so it has no kinetic energy.

The chemical energy store holds energy in chemical bonds, like food or fuel. A stretched rubber band stores energy due to its deformation, not a chemical reaction.

The thermal energy store relates to temperature. Stretching a rubber band does not significantly change its temperature — the stored energy is due to the stretching itself.

The elastic potential energy store is correct — it is defined as energy stored in a stretched or compressed object, which perfectly describes the stretched rubber band.