Which of the following is NOT a common effect of corrosion on nonmetals?

Corrosion typically refers to the degradation of materials, primarily metals, due to chemical reactions with their environment. Nonmetals, on the other hand, do not usually undergo corrosion in the same manner as metals; they may experience different types of degradation or damage.

When considering the effects listed, electrical conductivity is a key distinguishing factor. Nonmetals are generally poor conductors of electricity. Unlike metals, which have free electrons that allow for high conductivity, nonmetals do not possess this characteristic under normal conditions. Therefore, corrosion does not affect the electrical conductivity of nonmetals in the same way it does for metals.

The other effects mentioned, while they may not be traditionally classified under "corrosion," can indeed be observed in nonmetals. Structural weakening can occur due to environmental factors that lead to degradation, physical swelling can happen when certain nonmetals absorb moisture or chemicals, and color change can result from exposure to UV light or other environmental influences. Each of these effects demonstrates that nonmetals can certainly show signs of degradation, but their electrical properties remain largely unchanged by corrosion processes.