Never happens.
The faucet itself does not use any water. The rate at which the water leaves the faucet is dependent on the make of the faucet.
To know for certain, you'd need to measure your water flow from your faucet at the rate it was turned on, but if its a newer faucet, then if you have pretty good water pressure (60 psi), the faucet will only flow at 2.2 gallons per minute. Thus if you had the faucet fully open for seven hours you may have wasted as much as 92 gallons.
Same as multiplying any number by itself once or many times.
3,000,000,000,000,000,000,000,000,000,000,000,000 TIMES
Itself and any of its multiples and as many times you like.
The exponent
Whenever it gets turned on.
2
If you multiply 10 by itself 100 times you will get a googol. 1 googol = 10100
4 times
The term itself, none.
5 and 1/3 times