Electricity and Magnetism Answers

A spherical straight has a radius of 14.0 cm and a charge of 26.0 uC.Calculate the electric field and the electric potential at(a)r=10.0 cm (b)r=20.0 cm, and (c)r=14.0 cm from the centre.

A solid conducting sphere of radius 2.00cm has a charge of 8.00 uC. A conducting spherical shell of inner radius 4.00 cm and outer radius 5.00 cm is concentric with the solid sphere and has a charge of -4.00 uC. Find the electric field at (a) r=1.00 cm (b) r=3.00 cm (c)r =4.50 cm and (d)r=7.00 cm from the centre of this charge configuration.

A very large,thin flat plate of aluminium of area A has a total charge Q uniformly distributed over its surfaces. Assuming the same charge is spread uniformly over the upper surface of an otherwise identical glass plate, compare the electric fields just above the centre of the upper surface of each plate.

A sinusoidal transverse wave traveling in the positive direction of an x-axis has amplitude of 2.0cm, a wavelength of 10c and a frequency of 400Hz. If the wave equation is of the form

Obtain an expression for the fraction of a complete period that a simple harmonic oscillator spends within a small interval delta_x at a position x. What is its physical significance?

An iron has a power of 1000 W. How much energy will it electrically transfer each second?

A wire loop of resistance 10 ohm and radius 10cm is kept in the plane of this paper in a uniform magnetic field B the direction of B is perpendicular to the plane of the page and points out of it and it's magnitude is increasing at the rate of 0.50Ts. Determine the magnitude and direction of the induced current in the loop

The gravitational force between two concentrated ("point like") masses is very similc% in its

mathematical stricture to the electrostatic force between two concentrated charges. The •strenotn• of

these two forces is, however, vastly different. To illustrate this. consider the following exanpte.

Somewhere in outer space are two identical spherical dust grains, 50 gm in diameter,

density 2.5 gtcma. They are at a distance d meters apart If the grains were electrically neut•ai. free of

other external forces, and have negligible relative velocity initially, they would eventually collide

Now suppose that both grains are electrically charged, each having n •extra• electrons Fine the

minimum value Of n that would prevent the gravitational collision. Compare this with the approximate

total number of electrons contained in one grain.

A positive point charge q is placed on the +Y-axis at y = a, and a negative point charge —q is placed

on the -y-axis at y = -a. A negative point charge - Q is located at some point on the + x-axis-

(a) In a free-bocy diagram. show the forces that act on the charge -Q.

(b) Find the x- and y-components of the net force that the two charges q and -q exert on -Q. (Your

answer should involve only k, q, Q, a and the coordinate x of the third charge.)

(c) What is the net force on the charge -Q when it is at the origin (x = O)?

(d) Graph the y-component of the net force on the charge - Q as a function of x for values ot x

between -4a and +4a.

1.A continuos line of charge lies along the x axis, extending from x= x0.to positive infinity.the line carries positive charge with a uniform linear charge density.what are (a) magnitude and b) direction of electric field at the origin.


2.consider a long cylindrical charge distribution of radius R with a uniform charge density p.find the electric field at distance r from the axis where r<R


3.a solid sphere of radius 40.0cm has a total positive charge of 26.0 uniformly distributed throughout it's volume calculate the magnitude of the electric field a)0cm b)10.0 cm c)40.0 cm d)60.0 cm from the centre of sphere