please explain to me what is the difference between dual core and core 2 duo.any answer will be appreciated!
I am giving you Intel specs since you refernce core 2 dual as AMD also sells duo core CPUs.
Basically a duo core cpu (Yonah family) has two intergrated CPUs on one die, or package and have a 2MB L2 cache that is shared by both cores.
A core 2 dual cpu offers more varients of this product (Mermon, Conroe, Allendale, Penryn and Wolfdale families) and have an L2 cache that starts at 2MB and goes to 6MB depending on the particular CPU you want/ buy/ have.
This LINK gives a really thorough explaination of Intels CPUs should you desire more specific information.