Transcript Electric Current Notes Electric_Current_Chap_23ppt

Electric Current Chap 23
True or False?

When a battery no longer works, it is out of charge and must be recharged before it can be used again.

T or F

A battery can be a source of charge in a circuit. The charge which flows through the circuit originates in
the battery.

T or F

Charge becomes used up as it flows through a circuit. The amount of charge which exits a light bulb is
less than the amount which enters the light bulb.

T or F

Charge flows through circuits at very high speeds. This explains why the light bulb turns on immediately
after the wall switch is flipped.

T or F

The local electrical utility company supplies millions and millions of electrons to our homes everyday.

T or F
Electric Current Chap 23



The battery supplies the energy needed to move a charge
from a low potential location to a high potential location.
The charge that flows through a circuit originates in the wires
of the circuit. The charge carriers in wires are simply the
electrons possessed by the atoms which make up the wires.
Charge moves abnormally slowly - on average, about 1
meter in an hour - through a circuit. Yet as soon as a switch
is turned to ON, charge located everywhere within the circuit
begins to move.
Electric Current Chap 23


The rate at which charge flows is everywhere the
same within an electric circuit. The rate at which
charge flows into a light bulb is the same as the
rate at which charge flows out of a light bulb.
An electrical appliance such as a light bulb
transforms the electrical energy of moving charge
into other forms of energy such as light energy
and thermal energy. Thus, the amount of
electrical energy possessed by a charge as it
exits an appliance is less than it possessed when
it entered the appliance.
Electric Current Chap 23

The battery simply supplies the energy to
do work upon the charge to move it from
the negative terminal to the positive
terminal.
Electric Current Chap 23
Electric Current Chap 23




Electric current is measured in amperes
A current carrying wire does not have a net
electrical charge.
Electrical charge and electrical current may
seem like the same thing, but are not.
Electrical charge can exert a force, current
is the motion of the force
Electric Current Chap 23

Ohms Law

Electrical Current = Electrical Potential Difference
/ Electrical Resistance
Current = Voltage / Resistance
 I = V/R
 1 ampere = 1 volt / 1 ohm

Electric Current Chap 23

Ohms game
Electric Current Chap 23
Quick points about Ohms Law
- Holds true for constant resistance, as the
temp. of the resistor increases the amount
of resistance will change
- Current seeks the path of least resistance
reason for the third prong
- Current may be different at different
locations throughout a circuit
Electric Current Chap 23
Electrical Power P is the rate at which
electrical energy E is converted to other
forms of energy (light, heat ect…)
P = E/t
Electric Power P in a circuit carrying a current
I across voltage V is equal to the product of
the current and the voltage
P = IV