Tensile stress (or tension) is the stress state leading to expansion; that is, the length of a material tends to increase in the tensile direction. The volume of the material stays constant. When equal and opposite forces are applied on a body, then the stress due to this force is called tensile stress.

Tensile stress is a quantity associated with stretching or tensile forces. Usually, tensile stress is defined as the force per unit area and denoted by the symbol σ. The tensile stress (σ) that develops when an external stretching force (F) is applied on an object is given by σ = F/A where A is the cross sectional area of the object. Therefore, the SI unit of measuring tensile stress is Nm-2 or Pa. Higher the load or tensile force, higher the tensile stress.

Tensile stress is the correct answer.

Explanation:
When an object undergoes dimensional changes, such as an increase in its length or volume, it experiences internal forces known as stress. Stress is defined as the force per unit area applied to a material. It is a measure of the internal resistance of a material to deformation.

There are different types of stress depending on the nature of the forces applied. In this case, the stress that is set up in the body due to an increase in its dimensions is called tensile stress.

Tensile stress occurs when a material is subjected to forces that tend to stretch or elongate it. It is also known as normal stress or axial stress. Tensile stress acts perpendicular to the cross-sectional area of the material and is defined as the force per unit area.

Under tensile stress, the material experiences an increase in length along the axis of the applied force. This is commonly observed in materials like rubber bands or springs when they are stretched. Tensile stress can cause the material to deform and eventually reach its breaking point, leading to failure.

Tensile stress can be calculated using the formula:

Tensile stress (σ) = Force (F) / Cross-sectional area (A)

Where the force is measured in Newtons (N) and the cross-sectional area is measured in square meters (m²).

In summary, the stress that is set up in the body due to an increase in its dimensions is called tensile stress. It is a type of stress that occurs when a material is subjected to forces that tend to stretch or elongate it. Tensile stress is defined as the force per unit area and acts perpendicular to the cross-sectional area of the material.