A very long conducting pipe (hollow cylinder) has inner radius a = 1.5 cm and ou
ID: 1397985 • Letter: A
Question
A very long conducting pipe (hollow cylinder) has inner radius a= 1.5 cm and outer radius b= 2.1 cm . It carries charge per unit length of + 670 nC/m . A line of charge lies along the axis of the pipe. The line of charge also has charge per unit length of + 670 nC/m .
1.For r<a, how does the electric field strength vary with distance r from the central axis of the pipe?
a.The field strength is independent of r.
b.The field strength is proportional to r.
c.The field strength is proportional to 1/r.
d.The field strength is proportional to 1/r2.
e.The field strength is proportional to 1/r3.
f.The relationship between field strength and r is more complicated than any expressed above.
2.For a<r<b, how does the electric field strength vary with distance r from the central axis of the pipe?
a.The field strength is independent of r.
b.The field strength is proportional to r.
c.The field strength is proportional to 1/r.
d.The field strength is proportional to 1/r2.
e.The field strength is proportional to 1/r3.
f.The relationship between field strength and r is more complicated than any expressed above.
3.What is the charge per unit length on the inner surface of the tube?
4.What is the charge per unit area on the inner surface of the tube?
5.What is the charge per unit length on the outer surface of the tube?
6.What is the charge per unit area on the outer surface of the tube?
Explanation / Answer
1) c.The field strength is proportional to 1/r.
2) c.The field strength is proportional to 1/r.
3) 0, for conductors charges are found only outer outer surface.
4) 0, for conductors charges are found only outer outer surface.
5) + 670 nC/m
6) (670 nC/m)/(2*Pi*b) = 50.78nC/m^2
I am very sorry! I read not right teh problem.
2) a.The field strength is independent of r. (inside the conductor there is not electric field, that is field = 0)
3) -670 nC/m
4) (-670 nC/m)/(2*Pi*a) = -71.09 nC/m^2
5) 2*670 nC/m = 1340 nC/m
6) (2*670 nC/m)/(2*Pi*b) = 101.56 nC/m^2