Introduction:
In structural engineering, an L-section is a type of beam cross-section that resembles the shape of the letter 'L'. When an L-section beam is subjected to a transverse shear force, the shear stress distribution across the section can be analyzed. The question asks about the layer in the L-section where the maximum shear stress is developed.

Understanding Shear Stress:
Shear stress is a measure of the force per unit area acting parallel to the surface of a material. In the case of an L-section beam, the shear stress distribution can be visualized as a shear flow across the section.

Shear Stress Distribution:
When a transverse shear force is applied to an L-section beam, the shear stress distribution is triangular in shape. The shear stress is maximum at the neutral axis of the section and decreases linearly towards the top and bottom edges of the flange.

Explanation:
The neutral axis is the axis in the L-section beam where there is no tension or compression. It is the location where the bending stress is zero. In an L-section beam, the neutral axis is located at the centroid of the section.

Since shear stress is directly related to the bending stress, the shear stress distribution follows a similar pattern as the bending stress distribution. Therefore, the maximum shear stress is developed at the neutral axis of the L-section beam.

At the top edge of the flange, the shear stress is lower than at the neutral axis because the distance from the neutral axis is greater. Similarly, at the bottom edge of the flange, the shear stress is also lower than at the neutral axis due to the larger distance from the neutral axis.

Conclusion:
In an L-section beam subjected to a transverse shear force, the maximum shear stress is developed at the neutral axis of the section. This is because the neutral axis is the location where the bending stress is zero, and shear stress distribution follows a similar pattern as the bending stress distribution.