Answer:Given below
Explanation:
given
charge on inner sphere=-[tex]1.6\times 10^{-6} C[/tex]
Charge on outer sphere =[tex]5.1\times 10{-6} C[/tex]
Consider a gaussian surface of radius (a)0.20 m
net charge inside =[tex]3.5\times 10^{-6} C[/tex]
Electric field[E]=[tex]\frac{KQ}{r^2}[/tex]
E=[tex]\frac{9\times 10^{9}\times 3.5\times 10^{-6}}{0.2^2}[/tex]
E=[tex]787.5\times 10^3 N/C[/tex]
Field direction is outward normal
(b)r=0.1m
Charge enclosed=[tex]-1.6\times 10^{-6}[/tex]
Electric field[E]=[tex]\frac{KQ}{r^2}[/tex]
E=[tex]\frac{9\times 10^{9}\times 1.6\times 10^{-6}}{0.1^2}[/tex]
E=[tex]-1440\times 10^{3} N/C[/tex]
Field direction is Inward normal
(c)r=0.025 m
As the guaussian surface is inside the smaller sphere therefore electric field is zero.