electrostatic potential and capacitance Flashcards
potential is a _ qty
scalar
potential due a point charge
KQ/R
potential at axial.point of dipole
kp/r²-a²
potential at equitorial point of a dipole
0
potential due to uniformly charged thin sphere (outside)
kq/r (r=distance from centre)
potential due to uniform charged thin spherical shell inside and at surface
kq/R (R is radius)
relation between E, V and r
E=-dV/dr
in direction of electric field, potential _
decreases
potential energy in system of two charges is given by
Kq1q2/r
potential energy in system of 3 charges is given by
K[q1q2/r12+q2q3/r23+q3q1/r31]
potential energy of dipole in uniform E
-P.E
what is electrostatic shielding
making any region free from E
E decreases/increases due to dielectric
decreases by K times
dielectric constant and electric susceptibility relation
K=1+X
capacitance formula
Q/V
Capacitance depends only on
size and shape of conductor, permittivity of surroundings, presence of another conductor
parallel plate capacitor formula
EoA/d
capacitance of parallel plate capacitor on adding dielectric
C=EoA/(d-t+t/K)
t= thickness of dielectric
energy stored in capacitor
1/2CV²
relation between Q and C for retribution of charges
Q1’/Q2’=C1/C2
common potential formula
V=q1+q2/(c1+c2)
out of Q, C, E, U, V
which are affected by K when battery is disconnected
V, E, U decrease by K times
C increases by K times
out of Q, C, E, U, V
which are affected by K when battery is connected
Q, C, U increase by K times
n drops of same size and potential join to form a single big drop
what is the potential of this drop?
V×(n^2/3)
on inc separation between 2 charges , U-
inc or dec depending on the charges
%Delta formula
(final-initial)×100/initial
Relation between K, insulation and polarisation
K inc, insulation dec, polarisation tougher
angle between equipotential surface and lines of force
90
