What does this rebus riddle means ?

Decode this picture on T-Shirt and tell what it says ?

You can hear me, but you can't touch or see me.

What am I?

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

You are confined in a room and given two metal rods. Out of these two rods, one is magnet and the other is the iron rod. They look starkly similar. You don't have any other metal object in the room.

How will you decide which one of those is magnet?

Replace the question mark with the correct number.

Two old friends, Jack and Bill, meet after a long time.

Three kids
Jack: Hey, how are you, man?
Bill: Not bad, got married and I have three kids now.
Jack: That's awesome. How old are they?
Bill: The product of their ages is 72 and the sum of their ages is the same as your birth date.
Jack: Cool..But I still don't know.
Bill: My eldest kid just started taking piano lessons.
Jack: Oh, now I get it.

How old are Bill's kids?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.