iPad says its charging but won't turn on

So for school we were all given an iPad air back in 2014 and for the last couple of months the iPad has been completely dead but when I plug it in I charge the symbol comes up that its connected but hasn't actually turned on. Tried refreshing, different adapters, I've charge it without touching it for about 2 weeks and still won't turn on. I need to give it back to the school tomorrow as year 10 upgrade to mac book but I don't want to be charged for a non-working iPad.

Someone please help!!

Thanks, jacinta