What factors can cause a false perception of flux?

[-EquinoX-]

Homework Statement

1. http://img16.imageshack.us/img16/61/falsec.th.jpg

2. http://img16.imageshack.us/img16/5558/false.th.jpg

Homework Equations

The Attempt at a Solution

This is false, however it seems true.. I see no reason why it is false.. Can someone please help me to explain whY?

 

[eok20]

For 1. Consider the position of the rectangles: one could be parallel to F and the other could be perpendicular to it.