Proton-beam therapy involves firing high-energy protons at a tumor. The protons burrow into the tumor, coming to rest. The kinetic energy lost by the protons goes into the tumor, bursting its DNA, thus killing its cells. In one case, 0.1 Joules of proton energy is desired to be deposited in a tumor. The protons are accelerated from rest through a 10 Mega Volts potential difference to create a proton beam. 

1. What is the total charge of the protons that must be fired at the tumor to deposit the required energy? 

2. How many protons is this? 

3. How many Watts is this if the beam is only on for 250 microseconds?