Electricity and Magnetism Answers

A 2D annulus (thick ring) has an inner radius Ri and outer radius Ro, and charge Q non-uniformly distributed over its surface. The 2D charge density varies with radius r by n(r)=Cr^3 for Ri<= r<=Ro and n=0 for all other r. C is a constant. Answer the following in terms of the variables given above. 1-Find an expression for C such that the total charge of the annulus is Q. Include the SI units for C next to your answer.

Draw a clear picture and use it to set-up the integral to calculate the E-field at a point on the axis of the annulus (this axis is perpendicular to the plane of the annulus) a distance z from the center of the annulus. You must complete all the steps short of actually computing the integral( your final answer must be an integral with only one variable of integration and all other variables constant.) Show that your answer has the correct SI units for the electric field.

The airgap in a magnetic circuit is 1.1 mm long and 2000 mm2 in cross-section. Calculate: (i) the reluctance of the airgap; and (ii) the m.m.f. to send a f lux of 700 microwebers across the airgap.

A 50 loop circular coil has a radius of 3cm .it is oriented so that the field lines of a magnetic field are normal to the area of the coil .if the magnetic field is varied so that vector B increase from 0.10T to 0.35T in 2milliseconds,what is the average induced emf in the coil?

A coil of wire 8cm in diameter has 50turns and is placed in a B field of 1.8T. If the B field is reduced to 0.6T in 0.002seconds,what is the induced emf

A uniform magnetic field strength 0.50T is directed at an angle of 60° to a plane of 100 turn,rectangular copper coil of length 0.04m and width 0.05m. The diameter of the copper wire which make up the coil is 1.00mm and resistivity is 1.7×10^-8 ohms metre.The magnetic field through the loop decreases to zero in 0.3seconds ,Determine

1)The initial flux through the coil

2)The average induced e.m.f in the coil as the field decreases

The lithium atom has 3 electrons. Then the number of electrons in the negative ion in the lithium will be

A point charge Q1=3uc at origin and a point charge Q2=-7 uc is placed at x= 0.4m on the x axis or cartesian system.determine the electric field E(x)=E(x)x at all points along x axis

A heat lamp is used to treat a swollen leg. The lamp has an rms electric field of 3550 N/C. What is the maximum value of the electric field? What is the maximum intensity of the lamp? If the lamp if focused over a circular area of diameter 4.0 cm, what is the power delivered to the leg?

What is the critical angle for a diamond-air interface? What happens if a ray of light is incident at angles of 20degrees, 24degrees and 50degrees?

The indices of refraction of the core and cladding of an optical fiber are 1.5 and 1.40, respectively. Light is incident at the core at 70%. What is the distance between two successive reflections in the core it its diameter is 0.05mm?