When does a pinacol undergo dehydration or rearrangement? What happens when the above pinacol is treated with -
(a) conc. sulphuric acid
(b) dil. sulphuric acid 

I'm confused between pinacol rearrangement and dehydration (E1 or E2?), as both possibilities exist. I think the concentration of the reagent might have a role to play, but I'm not sure. Please help. 

P.S. It'd be great if you could quote data and sources with your answer.
When you treat pinacol with sulfuric acid, an E1 elimination will take place ( having a carbocation as intermediate ) and it forms pinacolone ( 3,3-dimethyl-2-butanone ). I am not aware of how concentrated the acid should be. Do you require a photo depicting the mechanism ?