Generated meshs and lights

Hi guys, i have a question regarding generated meshes and lights.

Code:

                 vertices.Add(new Vector3(0,0,0));
                 vertices.Add(new Vector3(20,0,0)); 
                 vertices.Add(new Vector3(20,20,0));
                 vertices.Add(new Vector3(0,20,0); 
 
                 uvs.Add(new Vector2(0,0));
                 uvs.Add(new Vector2(1, 0));
                 uvs.Add(new Vector2(1, 1));
                 uvs.Add(new Vector2(0, 1));
 
                 triangles.Add(0);
                 triangles.Add(2);
                 triangles.Add(3);
 
                 triangles.Add(3);
                 triangles.Add(1);
                 triangles.Add( 0);

                 mesh.vertices = vertices;
                 mesh.triangles = triangles ;
                 mesh.uv = uvs;
                 mesh.RecalculateNormals();

I added 10 of those meshes, just for testing (some with more than 2 vertices & triangles) Also im using the buildin mobile bumbed diffuse shader and i added an arena light to the scene.

Any idea why the mesh wont be affected by the light?

Thanks!