1. How much voltage must be used to accelerate a proton (radius 1.2E-15m) so that it has sufficient energy just to penetrate a silicon nucleur? A silicon nucleus has a charge of +14e and its radius is about 3.6E-15m. Assume the potential is that for point charges. 2. In the Bohr model of hydrogen atom, an electron orbits a proton (nucleus) in a circular orbit of radius 0.53E-10m. (a) What is the potential at the electron's orbit due to the proton? (b) What is the kinetic energy of the electron? (c) What is the total kinetic energy of the electron in its orbit. Thanks for helping!