Elements Of Electromagnetics
Elements Of Electromagnetics
7th Edition
ISBN: 9780190698614
Author: Sadiku, Matthew N. O.
Publisher: Oxford University Press
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Chapter 3, Problem 41P

(a)

To determine

The curl of vector field A and divergence of the curl.

(a)

Expert Solution
Check Mark

Explanation of Solution

Given:

The vector field (A) is x2yax+y2zay2xzaz.

Calculation:

Calculate the curl of vector field (×A) using the relation.

  ×A=(AzyAyz)ax+(AxzAzx)ay+(AyxAxy)az

  ×A=((2xz)y(y2z)z)ax+((x2y)z(2xz)x)ay+((y2z)x(x2y)y)az=(0y2)ax+(0+2z)ay+(0x2)az=y2ax+2zayx2az

Calculate the divergence of the curl ((×A)) using the relation.

  (×A)=(×A)xx+(×A)yy+(×A)zz

  (×A)=(y2)x+(2z)y+(x2)z=0

Thus, the curl of vector field A is y2ax+2zayx2az_ and divergence of the curl is 0_.

(b)

To determine

The curl of vector field A and divergence of the curl.

(b)

Expert Solution
Check Mark

Explanation of Solution

Given:

The vector field (A) is ρ2zaρ+ρ3aϕ+3ρz2ϕaz.

Calculation:

Calculate the curl of the vector field (×A) using the relation.

  ×A=(1ρAzϕAϕz)aρ+(AρzAzρ)aϕ+1ρ(AϕρAρϕ)az

  ×A=[(1ρ(3ρz2)ϕ(ρ3)z)aρ+((ρ2z)z(3ρz2)ρ)aϕ+((ρ3)ρ(ρ2z)ϕ)az]=[00]aρ+[ρ23z2]aϕ+[4ρ20]az=(ρ23z2)aϕ+4ρ2az

Calculate the divergence of the curl ((×A)) using the relation.

  (×A)=1ρρ(ρ(×A)ρ)+1ρϕ(×A)ϕ+z(×A)z

  (×A)=1ρρ(ρ×0)+1ρϕ(ρ23z2)+z(4ρ2)=0

Thus, the curl of vector field A is (ρ23z2)aϕ+4ρ2az_ and divergence of the curl is 0_.

(c)

To determine

The curl of vector field A and divergence of the curl.

(c)

Expert Solution
Check Mark

Explanation of Solution

Given:

The vector field (A) is sinϕr2arcosϕr2aθ.

Calculation:

Calculate the curl of the vector field (×A) using the relation.

  ×A=[1rsinθ((Aϕsinθ)θAθϕ)ar+1r(1sinθArϕ(rAϕ)r)aθ+1r((rAθ)rArθ)aϕ]

  ×A=[1rsinθ((0)θ(cosϕr2)ϕ)ar+1r(1sinθ(sinϕr2)ϕ(0)r)aθ+1r((r(cosϕr2))r(sinϕr2)θ)aϕ]=[1rsinθ(0sinϕr2)ar+1r(1sinθcosϕr2)aθ+1r(cosϕr20)aϕ]=sinϕr3sinθar+cosϕr3sinθaθ+cosϕr3aϕ

  (×A)=0

Calculate the divergence of the curl ((×A)) using the relation.

  (×A)=[1r2r(r2(×A)r)+1rsinθθ((×A)θsinθ)+1rsinθϕ(×A)ϕ]

  (×A)=[1r2r(r2(sinϕr3sinθ))+1rsinθθ(cosϕr3sinθsinθ)+1rsinθϕ(cosϕr3)]=1r2(sinϕr2sinθ)+1rsinθ(0)1rsinθ(cosϕr3)=sinϕr4sinθsinϕr4sinθ

Thus, the curl of vector field A is (sinϕr3sinθar+cosϕr3sinθaθ+cosϕr3aϕ)_ and divergence of the curl is 0_.

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Elements Of Electromagnetics

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