Light and Electricity

Light

a wave that we can see

Speed of light

300,000,000m/s

Light can

carry heat, has color, can be bright or dim

Ways light can be bent

by a lens, or reflected in a mirror

What makes light?

the movement of electrons in atoms produce light

Light gains energy by

electrons moving from lower to higher levels

When moving from lower to higher

they release energy

Electromagnetic spectrum

whole range of light

Light we see

only a small amount of all light

Visible light

light we can see, in the middle

Low end of ES

radio waves

High end of ES

gamma rays

Polarizer

partially transparent material that only lets one angle of light through

Two polarizers in the same direction

light not blocked

Two polarizers in different directions

light can be blocked

Electricity

the flow of charge, or electrons

Charged

when charge builds up on an object or material

Repel

like charges

Attract

unlike charges

Electric charge

depends on the number of protons and electrons

Conductors

allow charges to flow easily (loosely bound electrons)

Insulators

does not allow charges to flow easily (tightly bound)

Electric circuits

any closed path in which electrons can flow

Closed circuit

flow of electrons is possible

Open circuit

gap in the circuit, electrons can’t flow

Voltage (V)

can cause the flow of charges

Household electricity

alternating current

Voltage measure

volts

Current (I)

the amount of electricity flowing in a circuit

Current measure

Amperes (A)

Resistance (R)

property of a material to slow down electricity

More resistance=

less current if the circuit has the same voltage

Resistance measure

Ohms (Ω)

Ohm’s Law

relates voltage, current and resistance through the equation

Series

a single pathway circuit for electron flow

Open Circuit is because

a break anywhere in the path

Electrons will not flow

for a series circuit

Adding total resistance

decreases total current

Parallel

branched pathway is formed for the flow of electrons

Electrons have options

for a parallel circuit

Homes are wired in

parallel

Resistor in each branch

operates independently of the others