Electricity and Magnetism Answers

1-5. Two point charges, q1 = 8 µC and q2 = -5 µC, are separated by a distance r = 0.1 m. What is the magnitude of the electric force? Note: 1 µC = 10-6 C.

the metal plates of capacitor a has an area of 1m^2 separated by a diatance of 0.002m. if a pyrex glass is inserted in between the plates, (a) what will be the change in capacitance? (b) how much energy was stored after insertion if it has a potential difference of 12v?

starting from maxwell's equations derive wave equation for a uniform plane wave travelling in free space.

Consider a soot particle of mass m_soot = 1.0 nanogram (=1.0 x 10^-9 g = 1.0 x 10^-12 kg), which corresponds to a diameter of a few microns. Some number of electrons have been added to give the particle a total charge q_soot, suppose the collector has a total charge of q_collector = 1.0 x 10^-6 C and is small enough to be treated as a point charge at the rim of the smokestack. (a) if the separation between the collector and the soot particle is r = 0.10 m, what is the value of q_soot so that the electric force exerted on the particle is equal to its weight? (b) How many electrons must be added to the soot particle?

A toroid core has N = 1200 turns, length L = 80cm, cross-sectional area A = 60cm2

,

current I = 1.5A. Compute B and H. Assume an empty core.

The series combination of 5 F and 20 F capacitors is connected in parallel to 4 F capacitor. What is the energy stored in the combination of capacitors?

The series combination of 5 F and 20 F capacitors is connected in parallel to 4 F capacitor. What is the total charge stored in the combination of capacitors when connected to 100V

The series combination of 5 F and 20 F capacitors is connected in parallel to 4 F capacitor. What is the equivalent capacitance

Charges of q+ and q- at the two vertices of an equilateral triangle. What can be said of the electric field E and potential V at the unoccupied vertex?

1. A long, straight conductor carries a current of 200 A. At what distance from the conductor is the magnetic field

caused by the current equal to the Earth’s magnetic field?

2. A power cable contains two long parallel conductors placed 1.5 cm apart. It carries a current of 125 A to a 40 hp

electric motor. Find the force exerted on a 2.0 m length of one conductor?

3. A coil used to produce a magnetic field for an electron beam experiment has a radius of 15 cm and has 300

turns. What current is needed to produce a magnetic field of 5.0 x 10-3 T?