I just need help with part B & C. All work needs to be shown or else it is usele
ID: 2273258 • Letter: I
Question
I just need help with part B & C. All work needs to be shown or else it is useless to me. Here is all relevant information that may be needed:
A person who has become electrostatically charged is about to touch a large metal plate with his fingertip. The positive charge on his finger induces an opposite charge of equal magnitude on the surface of the plate.
There is a spark between the fingertip and the plate when the separation is 2mm. Approximate the system by treating it as a parallel-plate capacitor with plate area of 1 cm^2. Find (a) the potential difference between the finger and the metal plate; (b) the charge on the fingertip; (c) the force exerted on the finger by the charge on the metal plate.
Work I've done:
a) Potential difference
I. V=ed = 6,000 V * confirmed answer from text
e = 3 x 10^6 (dielectric strength of air)
d = 2.00 x 10^-3
(e)(d) = answer
b) charge on fingertip?
c) the force exerted on the finger by the charge on the metal plate?
Explanation / Answer
b) charge on the finger tip,Q=C*V
C=(8.854*10^-12*10^-4)/(2*10^-3) =4.427*10^-13 F
V=6000V
charge,Q=(4.427*10^-13*6000)=2.656*10^-9 C
c)
the charge at equlibrium will bedistributed into half;
so,
the force exerted on the finger by the charge on the metal plate,F=1/2*Q*e=0.5*2.656*10^-9*(3*10^6) =3.8*10^-3 N