Q:

Battery or power adapter problem?

I have a problem charging my battery.
When I plug my power adapter into my MacBook Pro, the power adapter's light turns green (it doesn't change to orange) and my monitor light turns on (which means the laptop is getting power from the adapter)—but the battery wouldn't charge. 

However, when I use my friend's power adapter, my battery does charge. 
Is there a problem with my power adapter or something else?

A:

PS: when I use my friend's magsafe it
  charges my MacBook Pro.

Sorry if this is too obvious, but if your friend's magsafe charger indeed charges the battery without any problems, then it certainly seems like the problem is in your charger. (Somewhere in it; the cord, magsafe adapter, or some other part.)

