Why is a complete image formed even if half of a lens or mirror ...

[Davideckstein7]

Why is a complete image formed even if half of a lens or mirror is blocked?
 
  What will be an ideal response?

Question 2

Explain as exactly as possible the way in which the central engine of active galaxies and quasars actually works. Why is the orientation so important?
 
  What will be an ideal response?

[maya.nigrin17@yahoo.com]

Answer to Question 1

While the image formed is only half as bright, each part of the objective sees and images the entire object.

Answer to Question 2

Matter from an accretion disk falls into a supermassive black hole. As it does so, it accelerates and emits energy. About 20 of the energy from the mass falling in (from mass-energy conversion, E = mc2 ) is radiated off. This energy may escape, or be absorbed by outer layers and re-radiated, or sent off as high-energy jets which give rise to radio lobes. What we see from Earth depends greatly on whether we see it from the side as radio lobes, or from the top as a blazar.

[Davideckstein7]

Great answer, keep it coming

[patma1981]

Thanks for the timely response, appreciate it