A diagnostic tube has a target with a length of 10 mm. The electrons are focused along a strip of the anode 2.5 mm wide.
a) At what angle (in degrees) should this strip be placed to yield an apparent focal spot size 2.5 mm x 1.5 mm.
b) Using this size target, what angle is required to obtain a 2.5 mm x 2.5 mm apparent focal spot?