When the temperature of an object is increased, its change in length is proportional to which of the following?

When the temperature of an object is increased, the change in length is governed by the principle of thermal expansion, which states that materials expand when heated. The amount of linear expansion that occurs is directly proportional to the initial length of the object and the change in temperature. This relationship can be mathematically represented by the linear expansion formula:

ΔL = α * L₀ * ΔT

Where ΔL is the change in length, α is the coefficient of linear expansion specific to the material, L₀ is the initial length of the object, and ΔT is the change in temperature.

This formula clearly illustrates that for a given material, the change in length (ΔL) depends on how long the object initially is (initial length) and how much the temperature is increased or decreased (temperature increase). Therefore, it is this combination of the initial length and the temperature change that determines how much an object will expand.

The other options do not accurately describe the relationship involved in thermal expansion. For instance, while volume expansion does occur with temperature changes, it involves different factors not directly comparable to linear changes, such as cross-sectional area, which is more relevant to different types of expansion.