An infinite line of charge with linear density ? 1 = 8.9 ?C/m is positioned alon
ID: 2125274 • Letter: A
Question
An infinite line of charge with linear density ?1 = 8.9 ?C/m is positioned along the axis of a thick insulating shell of inner radius a = 2 cm and outer radius b = 4.2 cm. The insulating shell is uniformly charged with a volume density of ? = -664 ?C/m3.
1)
What is ?2, the linear charge density of the insulating shell?
2)
What is Ex(P), the value of the x-component of the electric field at point P, located a distance 7.7 cm along the y-axis from the line of charge?
3)
What is Ey(P), the value of the y-component of the electric field at point P, located a distance 7.7 cm along the y-axis from the line of charge?
4)
What is Ex(R), the value of the x-component of the electric field at point R, located a distance 1 cm along a line that makes an angle of 30o with the x-axis?
5)
What is Ey(R), the value of the y-component of the electric field at point R, located a distance 1 cm along a line that makes an angle of 30o with the x-axis?
6)
For how many values of r: (2 cm < r < 4.2 cm) is the magnitude of the electric field equal to 0?
7)
If we were to double ?1 (?1 = 17.8 ?C/m), how would E, the magnitude of the electric field at point P, change?
Explanation / Answer
equation for an infinite line of charge: E=2k(?/r)
Where k = 9x10^9.
Make sure you convert your numbers to ?1 = C/m and r = meters.
E = 2(9x10^9)((1.7x10^-4)/(.085))