# Question on electric filed.

NOT HOME WORK QUESTION (itsfrom last year exam question)

## Homework Statement

electric field between two disk of radius of R and at distance D=a/2 is given by the following
n=charge density (Q/A) E_0= the constant 8.85*10^-12

E=(n/E_o)((1- (a/2)/(((a/2)^2)+(R^2))^1/2

for what value of the ratio of the plate radius to separation between the plates does the electric field at point x=a/2 deffer by 1percent from the result n/E_o for infinite sheets?
R/a=......

## Homework Equations

the equation for infinite sheet is E=n/2E_o

## The Attempt at a Solution

not sure how to approach this question
is it R/2a=0.01 then R/2a*0.01=50?
please can some one explain this to me!!

What the question means is that E = 0.99 n / $$\epsilon$$
or it could also be E = 1.01 n / $$\epsilon$$.