SCIENCE 2ND GRADING

is dual in nature, a partivle and a wave

light

as a particle, light carries with it bundles of energy called _______-

photons

are transverse oscillating waves composed of electric and magnetic fields

electromagnetic waves

em waves travels ina vacuum at the speed of

3.0×10^8 m/s

in em wave, the electric field is ______ to the magnetic field

perpendicular

em waves can travel even without

medium

em spectrum, left to right, frequencies ____— as the wavelengths _____—

increase, decrease

are the region in the EM spectrum with the longest wavelengths and the lowest frequencies in the em spectrum

radio waves

naturally egenrated in the atmosphere

extremely low frequency waves (ELF)

also called as the ‘‘myriameter band’’, used for military communications with submarines because f their ability to penetrate saltwater up to certain depths

very low frequency waves (VLF)

are used for long distance communications

low frequency waves (LF)

are commonly used for amplitude modulation (AM) broadcasting and air traffic control

medium frequency waves (MF)

are used in international broadcasting stations

high frequency waves (HF)

used in digital audio broadcasting and mobile radio systems

very high frequency waves (VHF)

commonly used in TV broadcasting, global pasitioning systems (GPS), wireless fidelity (wi-fi), and bluetooth technologies

ultra high frequency waves (UHF)

have frequencies higher than those of radiowaves; also have sub bands such as L-bands for GPS.

microwaves

are found between microwaves and visible light; invisible to the unaided eye but can be detected in the form of heat

infrared waves (IR)

in this year, he first recorded the thermal measurement at the far end of the red spectrum

1800, william herschel

infrared from the prefix ______ means _—

infra, below

only part of the em spectrum can be seen by unaided eye; different colors of light caused by differences in their subwavelengths

visible light

extends from violet spectra of the visible light through x-rays; most comes from sun, stars emits in all parts of the em spectrum

ultraviolet waves

least harmful of the three

UVA

most harmful, however absorbed by ozone layer

UVC

can cause sunburn because unlike IR, it causes chemical reaction on the human skin; causes skin to burn or change color; too much exposure can cause cellular damage in an organism and may cause production of free radicals in the body or even dna damage

UVB

this year, he successfully prove the existence of energy beyond the violet spectra of the vidible light, naming it ultraviolet (UV)

1801, john ritter

its region between the uv and gamma regions; wavelengths are so small, which is why energies carried x-ray and the gamma ray regions are described in electron volts (eV)

x-rays

x-rays were first observed and documented by _____- in _______

wilhelm conrad roentgen, 1895

are found at the end of the em spectrum; contains highest energy of all; produced by objects with very high energy

gamma rays

amount of energy released by atoms that travels in the form of electromagnetic waves. colliding atoms to emit radiation

ionization

radiowaves, microwaves, infrared, visible light

non ionizing

ultraviolet, x-ray, gamma ray

ionizing

loq energy, cannot penetrate the cells of organism, effectively produce vibrations and electric current, may cause photochemical reactions such as sunburn and thermal heating, affect organism through intentionally or accidentally ingested

non ionizing

high energy, can penetrate the cells of organism, exposure may alter one's dna, can cause biological damage, dying of cells or have cellular mutations such as cancer cells, affect fast growing cells such as hair and skin

ionizing

happens when you get high amounts of radiation exposure over a very short period of time, person undergoing a cancer treatment

acute exposure

occurs when a person is exposed to a small amount of radiation over a long period of time

chronic exposure

bouncing of light rays when it hits a surface

reflection

reflection of smooth surfaces

regular/specular

reflection of rough surfaces

irregular/diffuse

states that the angle of incidence is equal to the angle of reflection

law of reflection

reflective surfaces made up of glass

mirrors

are flat surfaces that reflect light and form an image of an object brought in front of it

plane mirrors

car side mirror, dental mirror, solar cooker

curved mirror

periscope, kaleidescope, bathroom mirror

plane mirror

technique used at least two rays to locate and describe the image

ray diagramming technique

image appearing at the back of the mirror

virtual images

refers to the left-to-right reversal in plane mirrors

lateral inversion

have their reflective surfaces bent outward

convex mirrors

have their reflective surfaces bent inward

concave mirrors

the line cutting through the center

principal axis

actual physical center of the mirror

vertex

center of the sphere from which the mirror is taken or the geometrical center of the mirror

center of curvature

distance from the center of curvature to the vertex of the mirror

radius of curvature

the midpoint of radius of curvature

focus

formed when rays converge

real

formed when rays diverge

virtual

right side up

upright

upside down

inverted

ratio of the image dimension to the object dimensions

magnification

converges rays of lightthat are traveling; thick middle, thin uppen and lower edges

convex lens

diverges rays of light that are traveling; thin middle, thick upper and lower edges

concave lens

C for

centre of curvature

F for

focus

P for

pole

f for

focal length

history tells us that magnets have come from __________

lodestones

where does the word lodestone from

anglo-saxon word ‘‘leading stone’’

they used in this time magnets as compass

chinese, middle ages

come in different shapes and sizes

magnets

magnetic materials are usually made up of metals such as

iron, cobalt, nickel, alloys

3 classification of magnets

permanent magnets, ferromagnets, electromagnets

they do not easily lose their magnetic properties; naturally occuring; creates own persistent magnetic field

permanent magnet

lose their magnetic properties after some time; when magnetic field is removed, they also lose their magnetic abilities (nails, iron objects)

ferromagnets

produced by the electric current flowing through a wire

electromagnets

magnets produce a ________

magnetic field

it is a region of space where a magnetic force is felt

magnetic field

lines to indicate the magnetic field

magnetic field lines

magnetic field characteristics

lines always originate from the magnetic north pole; field lines do not cross one another; the closer the magnetic field lines to one another, the stronger the magnetic field

‘‘like poles repel, opposite poles attract’’

basic magnetic rule

are produced by positive and negative charges

electric fields

in 1820, a danish scientist, tried to prove that electricity in entirely different from magnetism; accidentally discovered electromagnetism

hans christian orsted (1777-1851)

flowing charges produce current

electromagnetism

the direction of the forceon this current-carrying wire can be demonstrated by using the _________

right-hand rule

magnetitude of the force can be determined by using

F=ILB

when the current-carrying wire produces a magnetic field, the wire becomes an _________;

electromagnet

in this law, it is not only the change in the magnetic field that can produce an electric current but also the area where the magnetic field is perpendicularly applied; if the wire is moving, it causes electric current where the magnetic field is applied

faraday's law of electromagnetic induction

if the magnetic flux changes, then ____

electromagnet induction occurs

it has the ability to produce electricity

conductor

electrical to mechanical

electric motor

mechanical to electrical

generator

english scientist who observed electromagnetic induction by introducing a magnet into a coil of copper wire, producing a deflection in the galvanometer

michael faraday (1791-1867)

the changing magnetic field will induce a voltage, causing the current to flow through the wire

electromotive force (emf)

lenz’s law of electromagnetic induction, formulated by a _

german scientist, heinrich friedrich emil lenz (1804-1865)

this year, states that the direction of the current is induced ina conductor bya changing magnetic field, such that the magnetic field is created by the induced current opposes the initial changing magnetic field that produced it

1834

magnet and current is =

opposite

2 types of generator

alternating current(ac) and direct current(dc)

difference of alternating current(ac) and direct current(dc)

alternating current(ac) - changing; direct current(dc) - dili mag change

direction of the current is induced in a conductor by changing magnetic field

thumb

force

middle finger

current

index finger

field