Field Theory Answers

The following wave function represents a travelling wave:

y(x,t) = 8.31 / [1.62 + (1.92x−8.50 t )²]

where y and x are in cm, and t is in seconds. What is the phase speed?

1. Point charges q1 = −4.5 nC and q2 = +4.5 nC are separated by 3.1 mm, forming an electric

dipole. (a) Find the electric dipole moment (magnitude and direction). (b) The charges are in a

uniform electric field whose direction makes an angle of 36.9 ̊ with the line connecting the charges.

What is the magnitude of this field if the torque exerted on the dipole has a magnitude 7.2 × 10−9N ∙

m?

If you peel two strips of transparent tape off the same roll and immediately let them hang near each other, they will repel each other. If you then stick the sticky side of one to the shiny side of the other and rip them apart, they will attract each other. Give a plausible explanation, involving transfer of electrons between the strips of tape, for this sequence of events.

An electron experiences a force f given as (f=3.2i ---2.7j)×10^-13N when passing through a magnetic field B=0.72kJ. calculate the velocity of the electron?. Take the electron charge Q=1.5×10^-19cou.

Prove that electric field and electric potential are connected by the formula E=V/r

The earth is 4times the size of the moon and acceleration due to gravity of the earth is 80times that of the moon. Calculate the ratio of the mass of the moon to that of the earth.

Two parallel plates at a distance of 0.008m apart are maintained at a potential difference of 600v with the negative plate earthed, calculate the electric field strength around the plates.

Lucy and her bike together have a mass of 120 kg she slows down from 4.5m/s to 3.5 m/s how much kinetic energy does she lose

For the vector feild F= (3x -y) I+(x+z)j+(2y-z)k find the following:

(I) the Magnitude of Vector F and the unit vector along vector F at the point (1,1,0)

(ii)the point at which the magnitude of vector F is 6 and the direction of vector F is along the unit vector (2i+2j+k)✓3

Find the divergence of the following vector feild.

(i) 3xi+(y-3)j+(2-z)

(ii) Zxi+Xyj+Yzk