SCIENCE
L1: ELECTROMAGNETIC WAVES
MECHANICAL → requires medium
LONGITUDINAL
sound waves
TRANSVERSE
water waves
electromagnetic
ELECTROMAGNETIC → do not require medium
Radio
Microwave
Infrared
Visible light
Ultraviolet
Xray
Gamma
MECHANICAL WAVES
LONGITUDINAL → compression → refraction
TRANSVERSE → chest and through → perpendicular
CREST → highest
THROUGH → lowest; minimum value
WAVELENGTH → distance between crest to crest, though to through
AMPLITUDE → distance between x axis
ELECTROMAGNETIC [reflected and refracted]
→ travels in all direction → can travel through vacuum
→ electromagnetic with magnetic field
→ perpendicular: equal EM and MF
PRODUCTION OF EM WAVES:
→ travels in all direction
→ Frequency → physical value
→ wavelength → size of em
→ EM waves are transverse
→ travels at 3×108m/2
→ reflected and refracted
→ emitted and absorbed by matter
DISCOVERY
JAMES CLERK MAXWELL
→ discovered EM waves
→ travels in empty space [vacuum]
→ changes = generation of field
FORMULA:
c = fλ
Frequency: f=c/λ
Wavelength: λ=c/f
L2: ELECTROMAGNETIC SPECTRUM
RADIOWAVES
used in communications → FM - MUSIC → AM - Khz
converted to sound waves through antenna
GLOBAL POSITIONING SYSTEM (GPS)
accurate distance
MAGNETIC RESONANCE IMAGING (MRI)
short radio waves with magnet
MICROWAVES
very short
RADIO DETECTION AND RANGING (RADAR)
find speed bu sending radio waves
INFRARED RAYS
most noticeable
takes pictures of satellites
shows temperature
THERMOGRAM → different temperatures
THERMORUB → identifying the temp
VISIBLE LIGHT
bends when enters a new medium
LONGEST → RED LIGHT
SHORTEST → VIOLET LIGHT
ULTRAVIOLET RAYS
high energy
UVA → aging and cataracts
UVB → skin cancer
UVC → dangerous but don’t penetrate
→ used to kill bacteria (sterilization)
→ to identify fake bank notes
→ used in paints
X-RAYS
dangerous
great amount of energy
bones and teeth absorb s-rays
penetrates skin and muscle
→ used to build buildings
→ causes cancer
GAMMA RAYS
greatest amount of energy
nuclear fision
used in chemotherapy
heavenly bodies
nuclear bombs and weapons
L3: EFFECTS OF EM WAVES
IONIZING → x-ray and gamma
acts by removing electrons
can penetrate through things
NON-IONIZING
not enough energy to remove electrons
cannot penetrate through objets
radio, micro, etc
RADIOWAVES
warming of body
ACUTE RADIATION SYNDROME (ARS)
MICROWAVES
cataracts, skin burns
INFRARED
can damage eyes, blindness, night vision
UV RAYS
sunburns, cataracts, skin cancer
X-RAY
kills lung cells, radiation burns, mutations, carcinogens
GAMMA
destroy lung cells, gene mutations, cause cancers
carcinogenic factors - cancer
L4: MIRRORS AND REFLECTION
VISIBLE LIGHT
travels in straight line
bends when there’s medium
LIGHT RAY → path which light travels → 3×108m/s
REFLECTION → light bounces back as it hits surface
MIRROR → reflected surface
glass, metal coating (silver and alluminum)
→ insulators can’t reflect light
PLANE MIRROR
flat surfaces → commonly used
forms image based on what is shown in front
LAW OF REFLECTION
ANGLE OF INCIDENCE = ANGLE OF REFLECTION
→ rays are reversible
→ all rays are measured with respect to N
→ 3 rays lie on the same plane
ANGLE OF INCIDENCE
point where light rays strike surface
INCIDENT RAY
produced by a the object that hit Pi
REFLECTED RAY
produced by incident ray after hitting Pi
NORMAL RAY
parallel to the rays
TYPES OF IMAGE
VIRTUAL IMAGE
formed in dimension of mirror
behind the mirror
no light rays formed the object
REAL IMAGES
formed in reality
light rays forms the image
IMAGE FORMATION
→ equidistant
Object distance → distance of mirror from object
Image distance → distance of image from the mirror
TYPES OF REFLECTION
SPECULAR (regular) → smooth surface
DIFFUSED → bumpy surface
TYPES OF MIRRORS
CURVED MIRRORS (spherical mirror)
plastic coated with silver/alluminum
CONCAVE → inward, coating inside
CONVEX → outward, coating outside
RAY DIAGRAMMING → uses 2 rays to locate image
PRINCIPAL AXIS → line at the center
CENTER OF CURVATURE → center of sphere
VERTEX - physical center of mirror
FOCUS → midpoint of radius if c
FOCAL POINT → distance from the mirror to focalP
IMAGE FORMATION ON MIRRORS
PARALLEL RAY → travels parallel to axis and bounce to hit focal point
FOCAL RAY → hits focal point and bounce directly
CHIEF RAY → pass through c and bounce back
CONCAVE MIRROR SPECIAL CASES
CASE 5: object between f and V
L - behind
O - upright
S - magnified
T - virtual
CASE 4: obj at F
L - infinity
O - inverted
S - magnified
T - real
CONVEX MIRROR
→ behind mirror and no focal point
L - behind mirror
O - upright
S - diminished
T - inverted
DETERMINING LOST
di - (+) real | (-) virtual
m → =1 - same | <1 - smaller | >1 - larger
- (+) upright | (-) inverted
RADIUS → 2f
L5: LENS
LENS - transparent, focuses light and forms image
→ eyes is always bi-convex
BICONVEX LENS (converging)
SPECIAL CASES BICONVEX
CASE 4: object at F
LOST → NO IMAGE FORMED
CASE 5: object between F and oc
L - same size
O - upright
S - magnified
T - virtual
CASE 6: object at infinity
L - focal point
T - real
BICONCAVE LENS (diverging)
→ negative focal
→ di should be negative answer
→ rays away from normal
SPECIAL CASES BICONCAVE
CASE 1: obj infront of biconcave
L - same side
O - upright
S - smaller
T- virtual
CASE 2: obj at infinity
L - focal point
T - virtual
→ ALWAYS smaller, virtual, upright
L6: OPTICAL INSTRUMENTS
EYE
image formed by corona and convex lens
image created in retina (inverted) → brain process to be upright
di = 0.017 / 17mm → fixed
pupil regulates light rays so it becomes smaller
OPTICAL INSTRUMENTS
CAMERA
→ lightproof chamber
→ smaller hole = sharper
TELESCOPE
appear nearer and magnified
uses lens and mirror
refracted - lens
reflective - mirror (newtonian reflector)
terestrial telescope
astronomical telescope
BINOCULARS
area to area (for 2 eyes) → biconvex and biconcave
MICROSCOPE
macro objects → convex lens
concave mirror
L7/8: MOTOR AND GENERATOR
ELECTRICITY → motor → selonoid
MAGNETS → permanent magnetic field → transformers
ELECTROMAGNETISM (physics)
→ study of electricity and magnets = energy
MAGNET
move other metal
same: repel | opposite: attract
LEVITATE: same pole → magnet (Maglex)
magnets can produce motion
electric current in a wire produce magnetic field
no energy = no magnetic field
MOTOR → electricity to mechanical
FLHR → flemming left hand rule
thumb - force
index - magnetic field
middle - current
LOOP OF CURRENT - wire spind continuously
a motor uses magnets to create motion
GENERATOR → mechanical to electricity
FRHR - flemming right hand rule
alternating current
axle - rotated by external force → fallingwater, steam
PARTS OF MOTOR AND GENERATOR
ARMATURE/ ROTOR
reacts to permanent magnetic field
electromagnet → carrying conductor
GENERATOR — armature outside
COMMUTATOR (motor)
receives electricity for rotor’s electricity (direct current)
SLIP RINGS (generator)
connected to ends of armature
helps in rotation
BRUSH
connected to slip rings for rotation
conducts current to moving parts
STATOR
holds the magnet to prevent attraction
permanent magnetic field
generator - converts mf to electric current
motor - mf that rotates armature
SHAFT/AXLE
MOTOR — SHAFT
connected to armature
holds rotation of armature
GENERATOR — AXLE
rotated by external force — falling water, wind
SELONOID
carrying conductor of electricity