Energy problem

A charge of 1 µC is distributed uniformly along the circumference of a circle with a radius of 30 cm. How much external energy is required to bring a charge of 61 µC from infinity to the center of the circle? Let ke = 8.98 x 109 nm2/C2. Answer in units of J.

Capacitance problem

When a potential difference of 178 V is applied to the plates of a parallel-plate capacitor, the plates carry a surface charge density of 47nC/cm^2. What is the distance between the plates? Answer in units of micrometers. I know that d = (epsilon * V)/sigma. I think my unit conversion is incorrect.

Equipotential Problem

Additional Problem 1: A hydrogen atom when in its lowest energy state consists of a proton of charge +e and an electron of charge -e and mass 9.1x10-31 kg. In the Bohr model of the atom, the electron moves around the nucleus in a circular orbit of radius 0.51x10-10 m. Determine the speed that another electron, starting very far away from the hydrogen atom, must have in order to ionize the atom during a collision. In the final state, all three particles (proton and two electrons) are considered at rest very far from each other. (a) construct a pictorial representation showing clearly the initial and final situations. (b) Choose a system. Construct work-energy bar graphs for this proc... click for more

How do you apply the binomial approximation

Consider a dipole consisting of two charged particles on the x axid, one with positive charge q+ located at x=+1/2d and one with negative q- charge located at x=-1/2d a) Derive an exact expression for the three dimensional potential field created by this dipole at a point P whose coordinates are {x,y, and z}...See attachment

Resistance of a wire

A wire with resistance R is lengthened to 2.28 times its original length by pulling it through a small hole. What is the resistance of the wire after it is stretched in units of R.