I\'m trying to find the resistance of a hollow cylinder in units of M W . The qu
ID: 1967500 • Letter: I
Question
I'm trying to find the resistance of a hollow cylinder in units of MW. The question is detailed this way:
A resistor is constructed by forming a material of resistivity 3 × 10^5 W · m into a shape of a hollow cylindrical shell of length 3 cm and inner radius of 0.52 cm and outer radius 1.85 cm. In use, a potential dierence isapplied between the ends of the cylinder, producing a current parallel to the length of thecylinder
Resistance is detailed as R = pl/A
My attempt:
p = 3 x 10^5
l = 3
r1 = 0.52
r2 = 1.85
A = cross-section of area = pr^2
A = p(r2 - r1)^2
= p(1.85^2 - 0.52^2)
= p(3.1521)
= 9.90261
R = (3 x 10^5)(3)/(9.90261)
= 90885 W
However, this isn't the answer I'm looking for as it's only in W, and not MW.
Explanation / Answer
= 3*105
L= 3cm= 0.03m
A= r12 - r22 = (r12 - r22 )= (0.01852 - 0.00522)= 9.9*10-4
R= L/A = 3*105 * 0.03 / 9.9*10-4 = 9.0886 M