The price is related with different size and specification you want? Different requirement, different cost, different price.
CenOptics, edmondoptics, foctek,thorlabs are just some of the suppliers
8
A pair of plane mirrors cannot serve as effective retroreflectors on the Moon because they would only reflect light back in the direction it came from if they are perfectly aligned. Any slight misalignment would cause the reflected light to disperse, preventing accurate reflection back to the source. Retroreflectors, such as corner-cube prisms, are designed to reflect incoming light back to the source regardless of the angle, making them far more suitable for lunar applications.
8.
A cube has 24 corners and 6 faces.
8 of them
A cube has 8 vertices. Each corner of a cube is a vertex where three edges meet.
If you define a corner as a point where 3 edges meet, a cube has 8 corners. If you define a corner as an edge where two faces meet, a cube would have 12 "corners".
The shortest distance, through the body of the cube, is sqrt(22 + 22 + 22) = sqrt(12) = 3.46 inches.
In any of the corners
Yes of course. A vertex is a corner were several lines intersect. A cube has 8 Vertices.
A vertex of a cube is its corner points. A cube has 8 vertices and six faces. It also has 12 edges. A cube is a three-dimensional figure.