exam time baby Flashcards
high 2 low frequency
gamma (16-12), x ray(10), UV(8) ,light, infared(6-4), microwave 2), radiowaves tv longwave etc (1-8) all number to the power of 10
properties of electromagnetic waves
- waves originate from accelrating charges
- they transfer energy from one point to another
3.does no oscillate crets and troughs where field strongest
4.waves can travel through vaccum (3x10^8)
radio waves used for
fm radio or tv
microwaves used for
heating food and satellite comms
infared (below red) used for
nigth vision equipment
visible light
can detect with eyes made up of rainbow
ultraviolet
comes from sun
x rays used for
casting shadows on x ray film and scanning bags security
gamma rays
emitted during nuculear reactions can penetrate tissue
two types of waves
mech and electromagnetic
pulse
single disturbance in a medium.
1khz
1000 hz
1mhz
1,000,000 hz
v=fh and other nb is?
v= h divided by 1 divided by period
longitudal wave
a series of consecutive compressions and rarefractions move parallel to direction of propogation
particle movment of longitudal wave
vibrate backwards and forwards parral to prop
wave speed
speed at which compressions and rarefracrions move
speed of sound waves depends on
how closely packed togeter particles in the medium are (energy can transfer from one particle to the next)
how do we hear?
Sound Wave Reception: Sound waves travel through the air and reach the outer ear. These waves are essentially vibrations that carry energy.
Transmission in the Ear: The outer ear channels these vibrations into the ear canal, directing them toward the eardrum (a thin membrane). When the sound waves hit the eardrum, it vibrates.
Middle Ear Mechanics: The vibrations from the eardrum move a series of tiny bones in the middle ear called the ossicles (the malleus, incus, and stapes). These bones amplify and pass the vibrations to the inner ear.
Inner Ear Processing: The vibrations reach the cochlea, a spiral-shaped, fluid-filled structure. Inside the cochlea are thousands of tiny hair cells that move in response to the vibrations. This movement generates electrical signals.
Signal Transmission to the Brain: The auditory nerve picks up these signals and sends them to the brain.
Brain Interpretation: The brain processes and interprets these signals, allowing us to recognize sounds, such as speech, music, or environmental noise.
oscilloscope does
converts waves into trasverse wave patterns
higher frequency
higher pitch
high loud
high amplitude
at what frequencies can we not hear
20khz plus
ultrasound imaging
Sound Waves Sent: A small device called a transducer is placed on the skin. It sends sound waves at a frequency that’s too high for humans to hear.
Waves Echo Back: These sound waves travel into the body and bounce back when they hit something solid, like an organ or tissue.
Computer Processing: The returning echoes are picked up by the transducer, and a computer converts them into images on a screen. The speed and strength of the echoes help determine the shapes, sizes, and types of structures inside.
Image Display: The result is a live, moving image that shows what’s happening inside, making it helpful for observing things like blood flow or fetal development.
james maxwell
proposed that when charges accelerate there is a changing magnetic field surroundig them.
plancks constant (max planck)
6,63x10^-34 j.s
what did max planck propse
energy not emitted in continous manner but emitted in small energy parcels called quanta
wave particle duality
some aspects of emradiation can be explained better using a wave model while some a particle model
conversion for electromagentic radiation
1 micro meter times 10^-6
1 nano meter times 10^-9
a magnet is
an object which has opposite magnetic poles at each end
what type of magnet is an electromagnet
temporary magnet
draw magnetic field, and replusing an attracitng
did u do it
magnetic declination
earths magetic poles are not same as geographic poles, angle between magnetic north and geograohic true north is called magnetic declination
electrostatics
study of elec at rest
how are electrons added or removed
friction
in the triboelectric series
further two substaces apart the greater chargine effect will be
size of force with which charged objects attract or repel depends on
size of charge on object bigger=more
distance between charged objects smaller=more
Qe is
1.6 x 10 ^-19
two requirments befor chagre can flow
- circuit must be closed no breaks
2.charges mus have energy able to move
qe
q,6 times 10 to the negatuve 19
1nc is
1 times 10 to the negatuve 9
resistor factors
- the longer the conductor the greater its resistance
- greater the cross sectional area the smaller its its resistance
- the hotter the resistor the greater the resistance
- the type of material resistance is made form
what is a rheostat
an electral instrument used to control current by varying resitance
two househild items that use a rheostat
ovens and light dimmers
vi must always be given
yes
