Electricity and Magnetism Answers

A long straight wire is surrounded by a hollow metal cylinder whose axis coincides with that of the wire . The wire has a charge per unit length of density,and the cylinder has a net charge per unit length of2density from this information use the Gauss's Law to find (a)the charge per unit length on the inner surface of the cylinder (b) the charge per unit length on the outer surface of the cylinder, and (c) the electric field outside the cylinder a distance r from the axis.

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.