Electric Fields and Potentials. Joey Multari, Shannon Burt, Katie Abbott. Electric Force. Electricity exerts a force similarly to gravity. F e = kq 1 q 2 r 2
Joey Multari, Shannon Burt, Katie Abbott
Electricity exerts a force similarly to gravity.
Fe = kq1q2
where q1 and q2 represent the amount of charge in Coulombs (6.24 x 1018), r is in meters and k is the electrical constant (9 x 109 Nm2 /C2)
1 Coulomb of electrons travels through a 100-W lightbulb in about one second
D- Fast movement
E- Slow movement
Just like gravity field, charges have a force field (E) as well, measured in force per unit charge
E = F = kQ
where Q is a positive test charge
Direction of fields – away from a positive charge, toward a negative charge
Just like gravity—the potential (possibility) of falling to earth, charges have the potential to move toward or away from each other
Voltage = PE/Q
PE in Joules and Q in Coulombs
Electrons repel toward the outside of any conducting surface
Net charge inside is zero
Electrons flow outward evenly, but pile up on sharp corners
Shielding is important in electronic devices such as televisions and computers
Person in a car hit by artificial lightning. The lightning strikes the car and jumps to the ground bypassing the front tire arcing from the axle to the ground.
Capacitors can store charges on plates which are separated — as in Franklin’s Leyden jars
A capacitor in a simple
Charge Q stored:
The stored charge Q is proportional to the potential difference V between the plates. The capacitance C is the constant of proportionality, measured in Farads.
Farad = Coulomb / Volt
This machine is capable of producing very high electrostatic potential differences in the order of millions of volts
It works by friction of the belt with the rollers and separates charges at combs which take the charges to the dome and picks them up from the ground at the base
One pair of charges of 1 C each are 1 m apart
F = kq1q2/ d2
F = (9 x 109 N m2/C2)(1 C)(1 C)/(1-m)2
F = 9 x 109 N m2/C2)(1 C2)/1-m2
F = 9 x 109 N (repulsive)
10 times the weight of a battleship
What happens to the magnitude of the force as the charges get farther apart?
C- atomic number
D- atomic mass
Electrons surrounding nucleusmay be thought of as a cloudin which the total negativecharged is smeared out.
Put negatively charged rod on the right side...
Center of electron cloud shifts to the left.
Charged comb attracts neutralbits of paper