The correct answer is: C. Only on the geometry of the section.
The shape factor is a dimensionless quantity that is used to determine the strength of a structural member. It is defined as the ratio of the area of the cross-section to the second moment of area of the cross-section. The second moment of area is a measure of the resistance of a cross-section to bending.
The shape factor is a property of the cross-section of a structural member and does not depend on the material properties of the member. The shape factor is used in the design of structural members to ensure that they are strong enough to carry the loads that they will be subjected to.
The following are the explanations of each option:
- Option A: Only on the ultimate stress of the material. This is incorrect because the shape factor does not depend on the ultimate stress of the material.
- Option B: Only on the yield stress of the material. This is incorrect because the shape factor does not depend on the yield stress of the material.
- Option C: Only on the geometry of the section. This is correct because the shape factor is a property of the cross-section of a structural member and does not depend on the material properties of the member.
- Option D: Both on the yield stress and ultimate stress of material. This is incorrect because the shape factor does not depend on the yield stress or ultimate stress of the material.