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Answer: it is rocket 2
Explanation: I just took the test
Hope it's the right answer for you
Answer:
E = p*r / 2*e_o
Explanation:
Given:
- Volume of cylinder V = pi*r^2*L
- Surface area A = 2*pi*r*L
- permittivity of space : e_o
Find:
Electric field E at distance r from the axis, where r < R.
Solution:
Step 1: Application of Gauss Law
- Form a Gaussian surface within the cylinder with r < R. Th cylinder has two surfaces i.e curved surfaces and end caps. Due to long charge distribution the flux through is zero, since the surface dA of end cap and E are at 90 degree angle to one another; hence, E . dA = E*dA*cos(90) = 0. For the curved surface we have:
(surface integral) E.dA = Q_enclosed / e_o
Step 2: The charge enclosed (Q_enclosed) is function of r and proportional density:
Q_enclosed = p*V
Q_enclosed = p*pi*r^2*L
Step 3: The area of the curved surface:
dA = 2*pi*r*L
Step 4: Compute E:
E*(2*pi*r*L) = p*pi*r^2*L / e_o
E = p*r / 2*e_o
