I have the correct answers for this problem but I don\'t understand which equati
ID: 1469803 • Letter: I
Question
I have the correct answers for this problem but I don't understand which equations to use or how to do the calculations. It would be really helpful for someone to explain. The answers are given in BOLD.
The figure shows a cross section of a long cylindrical conductor of radius a = 2 cm, carrying a uniformly distributed current i = 30 A into the page. Evaluate B(x) at the values asked below.
a) B(x = 0.0 cm)? 0.0T
b) B(x = 0.5 cm)? 7.5x10-5 T
c) B(x = 1.0 cm)? 1.5x10-4 T
d) B(x = 1.5 cm)? 2.25x10-4 T
e) B(X = 2.0 cm)? 3.0x10-4 T
f) B(x = 3.0 cm)? 2.0x10-4 T
g) B(x = 4.0 cm)? 1.5x10-4 T
h) B(x = 5.0 cm)? 1.2x10-4 T
i) B(x = 6.0 cm)? 1.0x10-4 T
Explanation / Answer
given
a = 2 cm
I = 30 A
a) at r = 0
B = 0
b) at r(<a) = 0.5 cm
B = mue*I*r/(2*pi*a^2)
= 4*pi*10^-7*30*0.005/(2*pi*0.02^2)
= 7.5*10^-5 T
c) at r(<a) = 1 cm
B = mue*I*r/(2*pi*a^2)
= 4*pi*10^-7*30*0.01/(2*pi*0.02^2)
= 1.5*10^-5 T
d) at r(<a) = 1.5 cm
B = mue*I*r/(2*pi*a^2)
= 4*pi*10^-7*30*0.015/(2*pi*0.02^2)
= 2.25*10^-5 T
e) at r(=a) = 2 cm
B = mue*I/(2*pi*a)
= 4*pi*10^-7*30/(2*pi*0.02)
= 3*10^-4 T
f) at r(>a) = 3 cm
B = mue*I/(2*pi*r)
= 4*pi*10^-7*30/(2*pi*0.03)
= 2*10^-4 T
g) at r(>a) = 4 cm
B = mue*I/(2*pi*r)
= 4*pi*10^-7*30/(2*pi*0.04)
= 1.5*10^-4 T
h) at r(>a) = 5 cm
B = mue*I/(2*pi*r)
= 4*pi*10^-7*30/(2*pi*0.05)
= 1.2*10^-4 T
i) at r(>a) = 6 cm
B = mue*I/(2*pi*r)
= 4*pi*10^-7*30/(2*pi*0.06)
= 1*10^-4 T