Distributed charge density volume charge density surface charge density linear charge density.

Distributed charge density

volume charge density

surface charge density

linear charge density

3v )meter/(Coulombs

2S )meter/(Coulombs

)meter/(CoulombsL

cosr4

dydE

2o

L

r

x

r4

dydE

2o

L

2o

L

r4

dydE

22 yxr

x

y

dyr

r

x

r4

dydE

2o

L

22 yxr x

y

dyr

a

a 22222

o

L

yx

x

yx4

dyE

22o

L

ax

a

x2

x2

Ea

lim

o

L

y

x

Z

dE

cosr2

dydE

o

s

22

o

s

yz2

zdyE

22o

s

yz

z

r2

dy

o

s

2

o

s

2E

r2E

o

L

2or4

QE

100

1

0.01

1 100 r

E

aa 2/3222

o

saa

zyx4

zdydxE

y

x

Z

-a-a

a

a

finite size square sheetuniform charge density

E

r2

o

Q

4 rE u

r2o

Q

4 r E ds u ds

x y

zr

2enc2

o

Q4 r

4 r

E ds

o

encQ

dsE

requires symmetry

electric field

charge must be ENCLOSED within surface

positive or negative charge

direction of field

o

encQ

dsE

o

s

2E

sQ senc yx2Es2E

E

yx

E

yxs

o

encQ

dsE

a

z2

2E

o

s

sa

z2Q senc

yx2Es2E

within a charged sheet a

z

yx

za-a

o

encQ

dsE

yxa

z2s

L

o

E2

LQ Lenc

E s E 2 L

o

encQ

dsE

L

He showed that brewery gas extinguished lighted wood chips. When the heavy gas, as he called it, was dissolved in water, he found that it had a very pleasant and tangy taste. He had invented soda water. Acting on a suggestion in a letter from Benjamin Franklin, he showed that hollow charged vessels contain no charge on the inside and deduced that the electric force law is inverse square.

2o

QE

4 r

0Qenc

2E s E 4 r r < a

0E arb

brc

cr2

o

2QE

4 r

QQenc

Q2Qenc

0Qenc 0E

L2

o

E

2 a

2

enc L2Q L

a

E s E 2 L a

LL

L

ab

LQ Lenc L

o

E2

b 0Qenc 0E

0 a b

o

encQ

dsE

o

v

vdv

dvv

EdsE

o

v

E

“Lately I've been wondering where the slide rules went. Back in the 1960’s, slide rules were a prime accessory for those with a quantitative bent. They were suspended from belts long before calculators. In fact, they were the personal calculation engine of choice for almost three centuries.”

The principle of the slide rule was first enumerated by E. Gunter in 1623, and in 1671, S. Partridge constructed an instrument similar to the modern slide rule. The slide rule was an indispensable tool for scientists and engineers through the 1960’s.

In 50 years, the computer you are using to view this will be landfill, but your slide rule will just be nicely broken in.

It happens elsewhere other than under the Iowa Avenue bridge