Newton's Rings: Darker or Brighter Central Spot?

[oreo]

If light is transmitted at a point of contact in Newton's rings. The central spot will be darker or brighter?

 

[CWatters]

If you understand how Newtons rings are formed, what do you think and why?

 

[oreo]

If you understand how Newtons rings are formed, what do you think and why?

Actually I can't understand what the word "transmission at contact point" here means. I know that there is thin layer of air at contact point due to which there is phase shift of 180° which results in dark point at mid.

 

[CWatters]

I believe they are referring to the transmission method of creating rings..

Perhaps have a look at..
http://www.animations.physics.unsw.edu.au/jw/light/Newton's-rings.html#3b