Question

A disk with 
radius R has uniform surface charge density "sigma". a) by regarding the
 disk as a sereis of thin concentric rings, calculate the electric 
potential V at a point on the disk's axis distance x from thecentere of 
the disk.Assume that the potential is zero at infinity

• A. $\frac{\sigma R}{2{\epsilon }_0}$
• B. $\frac{\sigma R}{3{\epsilon }_0}$
• C. $\frac{\sigma R}{24{\epsilon }_0}$
• D. $\frac{\sigma R}{6{\epsilon }_0}$

Answer 1

The correct option is A $\frac{\sigma R}{2{\epsilon }_0}$

Potential due to uniformly charged disc$=\frac{\sigma }{2{ϵ}_0}\left[\right(R^2+x^2)1/2-x]$

$\sigma =$ Surface charge density on disc