Answer
(a) $ E = 2*10^{5} NC^{-1}$
$ V = 200v$
(b) $E= 2*10^{5} NC^{-1}$
$ V = 400v$
Work Step by Step
Area of the plate $ = A = 2.00cm *2.00cm =4.00 cm^{2} =4*10^{-4}m$
$q = 0.708*10^{-9}c$
(a) $ d= 1.00 mm = 10^{-3}m$
$ E = \frac{σ}{ε_{0}} = \frac{q/A}{ε_{0}} =\frac{q}{A*ε_{0}}NC^{-1}$
$ E =\frac{0.708*10^{-9}}{4*10^{-4} * 8.85*10^{-12}}NC^{-1}$
$ E = 2*10^{5} NC^{-1}$
$ V = \vec E. vec d = E*d = 2*10^{5} * 10^{-3} v= 200 v$
(b) $ d= 2.00 mm = 2*10^{-3}m$
Similarly
$E= 2*10^{5} NC^{-1}$
$ V = E*d = 2*10^{5} *2* 10^{-3} v= 400 v$
