Transcript Chapter 13 Electricity!

Chapter 13
Electricity!

Quick review:
Conductors
 Insulators
 Like charges ___________ and unlike
charges _____________.

Repel
Attract
 An
objects electric charge
depends on the imbalance of it
protons and electrons.
 Objects
can be charged by the
transfer of electrons.
 Charging
by Friction, Conduction
and ________________.

Electric Force = the force of attraction or
repulsion between object due to charge.

Electric Force depends on charge and
_______________.
Voltage and Current!

Volt is the SI unit for potential difference.
(voltage) (V)

A cell is a source of electrical current
because of the potential difference, or
voltage, between the terminals.

A voltage sets a charge in motion.
◦ Example: Electrons move from the negative
terminal of a battery to the positive terminal
when a flash is turned on.
 Current
is the rate that electric
charges move through a
conductor.
◦ Measured in Amperes (A)
◦ SI unit I

Resistance is the ratio of voltage across
a conductor to the current it carries.

Resistance is caused by internal friction
and slows the movement of charges.

Resistance = Voltage/Current
*Conductors have low resistance*
Practice problems

The heating element in an electric kettle
has a resistance of 30 Ω.

What is the current in the heating element
when it is connected to a 230 V supply?

A circuit contains a 6 volt battery and a
bulb with a resistance of 3 ohms.
Calculate the current.

What is the voltage of a circuit with 15
amps of current and toaster with 8 ohms
of resistance?

A circuit contains two 1.5 volt batteries
and a bulb with a resistance of 3 ohms.
Calculate the current.

You have a large flashlight that takes 6 Dcell batteries. If the current in the
flashlight is 2 amps, what is the resistance
of the light bulb? (Hint: A D-cell battery
has 1.5 volts.)__________________
Circuits!

Electric Circuit: an electrical device
connected so that it provides one or more
complete paths for the movement of
charges.
Series Circuit

Schematic Diagram: a graphic
representation of an electric circuit or
apparatus with standard symbols for the
electrical devices.

Key Parts of a circuit: