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Electricity & Magnetism

Megnetic effect of electric current: Field due to 4 wires.

"Consider the four current-carrying wires described in the figure below. Each of these wires is long and straight, and carries the current I either into or out of the page, as shown." What is the direction of the net magnetic field produced by these four wires at the center of the square? Please see attached for diagram.

Crossed Electric and Magnetic Fields

Show how an undeflected trajectory for a moving charge is obtained with appropriate crossed E and B fields. Draw seperate diagrams to illustrate your answer for a positive charge and a negative charge.

Electric and Magnetic Fields

A magnetic field has a magnitude of 12 T. What is the magnitude of an electric field that stores the same energy per unit volume as this magnetic field?

Magnetic Field

A 1140nF capacitor with circular parallel plates 1.12cm in diameter is accumulating charge at the rate of 20.7mC/s at some instant in time. What will be the induced magnetic field strength 10.8cm radially outward from the center of the plates? What will be the value of the field strength after the capacitor is fully charged?

Earth's magnetic field

Differentiate between the Earth's magnetic field and its production versus that of an ordinary bar magnet.

Proton source: Speed of the protons, radius of the final path

See attached file for the diagram. A proton source provides protons of various speeds. Protons of a particular speed follow the dotted line through the speed selector. The speed selector has an electric field of 3100 V/m and a magnetic field of 0.35T. The protons that the speed selector selects follow the dotted path.


A copper sulfate solution is placed in a container that contains coaxial cylindrical copper electrodes, as indicated in the picture. An electric field is created by connecting a battery across the electrodes as shown. A magnet field is created by immersing a magnet in the center of the solution as shown. Uncharged pollen g