Answer:2
Explanation:
Given
Cable has twice the length of cable B
and twice the radius(both inner and outer) of cable B
Inductance is given by
[tex]L=l\times \frac{\mu }{2\pi }\times \ln(\frac{R}{r})[/tex]
Where l=length
r=inner radius
R=outer radius
[tex]\mu [/tex]=Permeability of inner cylinder
suppose [tex]l_a[/tex] and [tex]l_b[/tex] be the length of cable A and B
so [tex]l_a=2l_b[/tex]
[tex]L_a=2l_b\times \frac{\mu }{2\pi }\times \ln(\frac{2R}{2r})[/tex]
[tex]L_a=2l_b\times \frac{\mu }{2\pi }\times \ln(\frac{R}{r})---1[/tex]
for wire B
[tex]L_b=l_b\times \frac{\mu }{2\pi }\times \ln(\frac{R}{r})---2[/tex]
divide 1 and 2 we get
[tex]\dfrac{L_a}{L_b}=2[/tex]