Physics: Waves and Electricity

amplitude

height of crest

wavelength

distance between two crests

wave velocity formula 1

wavelength / period (aka wavelength * frequency)

wave velocity formula 2

square root of frequency / linear mass density

linear mass density

mass per unit length

longitudinal waves

motion in the same direction as wave’s motion (ex. slinky)

transverse waves

motion perpendicular to wave’s motion (ex. snapping jump rope up and down)

intensity

the power put into something over the area it’s spread out

intensity formula

power / 4*pi*r²

How does a wave return when it hits an obstacle?

inverted (like backwards upside down)

How does a wave return if it doesn’t hit an obstacle?

the same

interference

2 waves running into each other

constructive interference

collision of 2 in-phase waves resulting in a wave with doubled values

destructive interference

collision of 2 completely-out-of-phase waves resulting in no wave

partially destructive interference

collision of 2 partially-out-of-phase waves resulting in a smaller wave

What type of wave are sound waves?

longitudinal

sound waves travel…

through any kind of matter but not a vacuum

sound waves produce sound by…

vibrating particles

speed of sound through air

340 m/s

sound is slowest through _

gases

sound is fastest through _

solids

pitch and frequency are _ proportional

directly

human audible range (in frequency)

20 Hz to 20,000 Hz

ultrasound

above 20,000 Hz

infrasound

below 20 Hz

doppler effect

pitch seeming to get higher as object approaches you

(electric) charging

transferring charge from an object to another

conduction

conductors isolated from the ground touch each other to transfer charge

induction

objects do not touch but are close to one another and use grounding

electroscope initial charge

neutral

when you touch electroscope with negatively-charged rod (conduction)…

electroscope becomes negative overall, and gold leaves will repel from each other

when you bring negatively-charged rod towards electroscope (induction)…

electroscope overall still has neutral charge, but gold leaves will repel because negative charge moves away from rod into leaves (to make permanent you’d have to ground it)pos

positive object & gold leaves move apart…

positive scope

positive object & gold leaves move closer…

negative scope

negative object & gold leaves move apart…

negative scope

negative object & gold leaves move closer…

positive scope

polarization

when negative and positive charges move to opposite sides of an object

electrical force equation

(k*|q1|*|q2|) / (r12)²

Coulomb constant (k)

9×10^9

Coulomb’s Law

each object exerts the same force on the other, and as the distance between 2 objects gets larger, the force gets smaller