1. parallel plate with capacitor of 20uF, plate is 0.5mm apart.(adsbygoogle = window.adsbygoogle || []).push({});

Find

1. Area of each plate

2. potential difference if there's a change of magnitude of 30uC on each plate.

3. stored energy

4. electric field between the two plates

5. charge density on the plate.

|_| |_|

|_____|

.5mm

I know [tex]C=\frac{Eo*A}{d}[/tex]

so would [tex]A=\frac{Eo*C}{D}[/tex] or A=Q / Eo *E

A= (8.85*10^ -12 ) * 20 / (.5 * 10^ -3) = 3.54 * 10 ^7 ?

2. three point charges on the x axis q1= (10uc) at x= -4m, q2= (-5uC) at the origin, q3= (-20uC) at x= 4m.

Q1(-4,0)...... Q2(0,0)...... Q3(4,0)

(+)----------(-)-----------(-)

10uC........ -5uC........ -20UC

Find

1. electric field at origin

2. force on q2

would electric field on orgin = Zero & force on q2 equal

[tex]F1= Ke\frac{q1|q2|}{r^2}[/tex] , [tex]F2=Ke\frac{|q3|q2|}{r^2}[/tex]

[tex]F1=\frac{(8.99* 10^9)* (10 * 10^ -6)*( 5*10^-6)}{(-4)^ 2}[/tex]

[tex]F2=\frac{(8.99* 10^9)* (20 * 10^ -6)*(5*10^-6)}{(4)^ 2}[/tex]

After this would i add components ( x i + y j )

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# Homework Help: Parallel plates & Point charge ?

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