- #1
Saitama
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Homework Statement
A charge ##(5\sqrt{2}+2\sqrt{5})## coulomb is placed on the axis of an infinite disc at distance ##a## from the centre of disc. The flux of this charge on the part of the disc having inner and outer radius of ##a## and ##2a## will be
A)##\dfrac{3}{2\epsilon_0}##
B)##\dfrac{1}{2\epsilon_0}##
C)##\dfrac{2(\sqrt{5}+\sqrt{2})}{\epsilon_0}##
D)##\dfrac{2\sqrt{5}+5\sqrt{2}}{2\epsilon_0}##
Answer: A
Homework Equations
The Attempt at a Solution
I have solved the given problem through integration but since this is an exam problem, I am wondering if there is a smarter way to solve this problem. Since the disc is infinite, I think we can use this fact to find a shorter method. Or is integration the only way to solve the problem?
Any help is appreciated. Thanks!