# three metallic plates a,band c carrying charges +Q,-2Q and +3Q are placed parallel to each other,where plate a and b are at a distance 'd' and b and c are at a distance '2d'.plate a and c are connected by a switch 's'.determine the charge appearing on each plate when switch 's' is closed and the charge flown through the the switch.

8 years ago
Use the simple concept of distribution of charge , and two paraller plates makes a capacitor, arrange the charges accrodingly.

sher mohammd
b.tech, iit delhi
Arun Kumar IIT Delhi
$Q_{a,left}=Q_{c,right}\\ Q_{a,right}+Q_{b,left}=0\\ Q_{b,right}+Q_{c,left}=0\\ Q_{a,left}+Q_{a,right}=Q1 \\Q_{b,left}+Q_{b,right}=Q2 \\Q_{c,left}+Q_{c,right}=Q3 \\adding\,all=>Q_{a,left}=(Q1+Q2+Q3)/2=Q_{c,right}=-Q/2 \\=>Q_{c,left}=Q3-Q_{c,right}=(Q3-Q2-Q1)/2=-3Q/2 \\=>Q_{b,right}=-Q_{b,left}=3Q/2 \\=>Q_{a,right}=-3Q/2$