PHYSICS 10 EXAMS

CIRCUITS

Unbroken loop of conductive material allowing electrical currents to flow continuously

Voltage (V)

energy that PUSHES electric charges to move

increase in voltage

more energy = more current = more brightness

Current (I)

the RATE at which a charge passes by a point on a circuit

Resistance (R)

OPPOSITION to the flow of electric current

Area and Resistance

Inversely proportional since there is less space for charges to flow

Length and Resistance

Directly Proportional since the current needs to travel longer

Resistivity and Resistance

Directly Proportional, low p = low R

Temperature and Resistance

Directly Proportional since increased temp. increases collisions between electrons

Voltage and Current, Resistance

Directly Proportional

Resistance and Current

Inversely Proportional

Series Circuit

Total V (add), Current = V/R, Total R (add)

Parallel Circuit

Total V (Constant), Total I (add), 1/R = 1/R + 1/R2…

Electric Energy

The total amnt of energy consumed over time.

Joules, kWh

Electric Power

The rate at which energy is consumed over time

Watts

Series Relationships

Up Power = Up Resistance = Up Voltage

Parallel Relationships

Up Power, Down resistance, Down Voltage

EM Waves

form of radiation created by oscillating electric and magnetic fields of vibrating charged particles

EM waves Difference from Mech Waves

can travel w/ or w/o medium, fastest in a vacuum

EM waves and Mech Waves Similarities

Carry energy from one place to another, don’t transfer matter

Electromagnetic spectrum

frequency & energy: increasing

wavelength: decreasing

radio waves

longest wavelength, lowest freq. and energy

military surveillance, radios, bluetooth

microwaves

high frequency radiowaves

mainly used for communication, weather forecast

infrared waves

cannot be seen by humans, but detectable as heat

all objects emit infrared radiation. thermal imaging

visible light

the only part of the spectrum that are visible to humans. dual nature; both a wave and a particle.

UV radiation

major source is the sun

X rays

high energy and freq, small wavelength. can be harmful to humans so hospitals control the time of exposure ; lead shields

Gamma rays

HIGHLY PENETRATING and harmful due to very short wavelengths and HIGH energy

Reflection

When light strikes a smooth shiny surface, it bounces off

Law of reflection

the angle of incidence = angle of reflection and incident ray, reflected ray, and normal line all lie in one plane

Refraction

bending of light as it passes from one medium to another due to a change in its speed

Dense Medium

More Index of Refr = More bend = less speed

Less dense to more dense

bend toward normal

More dense to less dense

bend away from normal

Convex Lenses

CONVerging, same LOST w concave MIRROR

Concave Lenses

diverges light rays, one set of LOST same w/ convex MIRROR

Cornea

dome-like structure covering the iris

Iris

colored muscle that controls pupil’s size to regulate light

Pupil

dark, circular opening that lets light pass through

Retina

layers of light-sensitive tissue where the image is formed

The Eyes’ Convex Lenses

clear structure behind the iris that fine-tunes focus onto the retina

Human Eyes image

real, inverted, smaller

Myopia - Nearsighted

longer eye, image forms infront of retina. concave lens can correct this

HYPEROPIA - FARSIGHTEDNESS

eye is shorter so image forms in front of retina. convex lens can correct