Electric Field and Potential

1.   a) What is the electric field of an iron nucleus at s distance of 6.00*10^-10 m from the nucleus? The atomic number of iron is 26. Assume that the nucleus may be treated as a point charge.
      b) What is the electric field of a proton at a distance of 5.29*10^-11 m from the proton? (This is the radius of the electron orbit in the Bohr model for the ground state of the hydrogen atom)

2.   What is an electrical arc? How and why does it occur?

3.   A small object carrying a charge of -55 microcoulombs experiences a downward force of 6.20 x 10-9 N when placed at a certain point in an electric field.

a) What are the magnitude and direction of the electric field at this point?.
b) What would be the magnitude and direction of the force acting on a copper nucleus (atomic number= 29, atomic mass= 63.5 gmol-1) placed at this same point in the electric field?

4.   A negative point charge q1 = -4 nC is on the x-axis at x = 0.6 m. A second point charge q2 is on the x-axis at x = -1.2 m. What must be the sign and magnitude of q2 for the net electric field at the origin to be a) 50 NC-1 in the +x-direction? b) 50 NC-1 in the -x-direction?

5.   A charge q1= -1 x 10-6 C is on the x-axis at x = 1.2 m, and the second charge q2 = + 2 x 10-6 C at x = 1.2 m and y = 1.6 m. a) Find the x and y-component of electric field at the origin 0. b) Find acceleration of a proton is released at the midpoint between q1 and q2.

Distinguish clealy between the electric field strength and the electric potential at a point.