Physics Flashcards
What impacts gravitational field the most?
Radius
The bigger the radius the more the gravitational field will decrease
How to convert days into seconds
1) find out how many seconds are in a day by
24hr x 60 (to get min) x 60 (to get seconds)
2) multiply that total by the amount of days asked in the question
Conversion tips
1) Determine which unit is bigger and which is smaller
2) Use chart to determine what to multiply / divide by
3) if small -> large = divide
if large -> small = multiply
Gravitational field
- Attraction acts to pull a smaller object towards s larger massive one.
Points towards the object (ex: arrows point towards the earth)
What happens to field strength if mass increases?
(look at formula to help you figure it out)
What happens to field strength if radius increases?
If the mass increases the field strength increases
If Radius increases the field strength decreases
Electrical field diagram
Negative = Charges attract towards
Positive = Charges attract away from
( santa’s elves turn bad and away from good)
(we can see this later when away from north pole and towards south pole in magnetic field strength)
Grounding
Providing a path for electrons to flow from an object towards the ground so that it becomes uncharged or neutral.
Magnetic fields: Ferromagnetic ( Strong magnets) where are the domains
- tiny magnetic ( domains inside)
- All magnets ( domains aligned)
Magnetic fields: what makes the Field strength increase and decrease
Decrease with distance (pulling apart)
Increase with strength of magnet
Magnetic fields: field lines
To determine direction use “north” test body
** Field lines go out of the north pole and into the south pole
(what happens to bad elves)
How does a motor work
1) As a current flows through the coil, a magnetic feild is generated
2) The magnetic field generated by the coil will interact with the permanent magnet.
3) Then can be used to make things spin and turn for different purposes ex: hair dryer
Motion cycle (when you have two the third is produced) What are the the three contents of this cycle.
1) Current / electrons (electrical field)
2) Magnet (magnetic field)
3) Motion / Movement
Generators
- Opposite energy conservations as motors
= generators convert mechanical energy into electric energy.
Motor produce mechanical energy
Generator produces electrical energy
List ways to make a stronger motor (x5)
1) Increasing number of coils
2) increase strength of magnet
3) changing magnet shape
4) increasing voltage
5) wrapping wire around metal
Alternating current ( + diagram)
= Electrons flow in both directions
(squiggly line diagram)
I
I vvvvvvvvvvv
——————-
Direct current ( + diagram)
= electrons flow in one direction in a current
(straight line diagram)
I
I —————–
——————
What do batteries create
Voltage
- Which is electrical potential energy that is available for work
What is resistance measured in
Ohms
Series circuit
Box circuit with no allies or pathways, have the most resistance (especially if theres more resistors)
Parallel circuit
Circuit with rows/pathways/allies within it, less resistance the more pathways there is.
3 ways we can be protected against electric shock
1) Fuses
2) Circuit breakers
3) Polarized Plugs
Fuses (what do they do)
If the current is too high \, ruse coordinator overheats and melts
as a safety precaution the circuit is ten broken to stop the current.
Circuit breaker
Opens circuit automatically if current is too high
If current rises above a safe level, breaker tips and circuit is broken
Ohm’s law ( what happens to the current if the voltage goes up?)
Current goes up volts go up
And as resistance goes up current goes down (resistors slow down current)
What are transformers used for?
To change voltage & current of the electricity being delivered
What are transformers made of?
= 2 coils of insulated wire wrapped around an iron core.
What’s the difference between primary vs secondary
Primary = receives input voltage
Secondary = supplies the output voltage
Step up
- voltage is increased (higher in secondary voltage)
- more secondary coils
Step down
- Voltage decreased
- more primary coils
- Higher current
How does a transformer work?
1) AC enters primary coil
2) causing a change in magnetic field which was magnified by iron core.
3) The change in magnetic field induces AC to second coil.
What principle used by transformers?
its called electromagnetic induction
What is currents relationship with resistance?
If Current goes up resistance goes down and vis versa.
They have an opposite relationship.
Parts of motor: Armature
Metal loop (THAT SPINS) uses its arms to stay between curved pieces of metal.
Parts of motor: Brush
Provides electrical contact.
Always maintain contact and allows commutator and armature to spin.
(when you brush your hair you’ll feel so good you may spin around)
Parts of motor: Commutator
Ring with gaps to help armature spin. interacts with permanent magnet.
Communication circle may have some gaps, this one has two which allow the current to switch direction.
what kind of current is used in transformer
AC
What is EMR
EMR is a wave that consists of changing electric feilds and a changing magnetic feild that travels at a right angle.
Wavelength vs frequency
Wavelength = Length of one cycle (meters)
(symbol = weird A)
Frequency = # of cycles /second (hertz) (f)
Types of EMR: Radio Waves
- Lowest Energy
- Lowest frequency
- Source = Vibrations of electrons within electric circuits
- Do not penentrate
- Are not ionizing
Types of EMR: Microwaves
- Source = High frequency vibrations of electrons within specialized electric circuit.
- Hazardous to Humans due to the high water content inside humans
- Are not ionizing
Types of EMR: Infrared
- Source = Emitted from a HOT object
- Can burn human skin
- Are Not ionizing
Ex: The heat we feel from the sunlight
Types of EMR: Visible light
Source = HOT objects such as sun, lightbulbs, and a fire.
- Can burn through air as well as the lenses in our eyes
- Are ** Not** ionizing
Types of EMR: Ultraviolet
Source = Very HOT objects such as the sun
- Mediacal equiptment Sterlizers
- Can burn ozone layer, as well as causing abnormal cell division (cancer)
- ** Some** are ionizing
UV light is why we wear sunscreen to protect us from the suns rays.
Types of EMR: X- Rays
Source is fast moving electrons striking a metal target, cna penetrate body tissue but not bones (thats why its used for examining bones)
Ionizing: Yes
Penetrate: Yes
Example: Radiation therapy
l
Do this in your notebook for all of them as review
Types of EMR: Gamma Rays
Source = Radioactive material
Penetrate = Yes metals, and cell division
Ionizing = Yes
Applications = Sterilize food
Reflected Light
- Bounces off an object
- A mirror is a perfect reflector
Law of Reflection
Angle of incidence is = to the angle of reflection
(equal on both sides / same angle)
Total internal reflection
= No light rays are transmitted through the medium and totally reflected back into the water.
Refraction
= When EMR waves bend, when they go from one medium to another
Diffraction
The scattering of light as it passes by an obstacle
- Can be applied to all EMR
Polarization
Confine a wave to vibrate only in one direction, helps reduce glare in sunglasses.
4 Steps on how stars are formed
1) All stars start out as nebula ( cloud of gas and dust)
2) The gas begins collapse and heat up due to its own gravitational attraction
3) Nuclear fusion when it gets really hot
4) EMR and energy is produced which prevents star from collapsing
Nuclear fusion
= 2 small nuclei join to form a larger nucleus releasing energy during the process
- Energy released = EMR (makes stars shine)
———Red stars are the coolest color and blue stars are the warmest———–
what is a stars life cycle dependent on?
Original mass of the star
Types of stars: Low-mass star
Fact = spend most of life fusing hydrogen into helium
(Spends the first part of life in nuclear fusion)
Sequence= NEBULA , LOW-MASS, RED GIANT, EXPANDING SHELL OF GAS, WHITE DWARF
R = Reindeer
E = Erin (is)
W= Wee
Or REW
Types of stars: Intermediate-mass star
Sequence= NEBULA, INTERMEDIATE STAR, SUPERGIANT, SUPERNOVA, NEUTRON STAR
S: Super Giant
S: Sports
N: News
What do all (mass) stars start off as?
Nebula
Types of stars: High-mass star
Sequence= NEBULA, HIGH-MASS STAR, SUPERGIANT STAR, COLLAPSING STAR, BLACK HOLE
S = Super Giant
C = Chicago
B = Bear
What are telescopes used for?
Study things in space by collecting EMR
Types of Telescopes: Simple Refracting telescope
(use what you already know about light)
= Magnifies an image by using lenses to bend light
Types of Telescopes: Reflecting telescope
(use what you already know about light)
What is the name of the popular large reflecting telescope?
If it has a mirror = reflecting telescope
- magnifies by reflecting light
= Hubble space telescope
Types of Telescopes: Radio
(use what you already know about light)
= They detect and record radio waves coming from stars
Types of spectrums: continuous
ALL colors and wavelengths are present
Types of spectrums: Emission
Bright lines emitted from an excited gas under low pressure
(was so excited it exploded with bright lines = emission)
Types of spectrums: Absorption
Has dark lines because wavelengths are being absorbed.
how do you analyze a spectrum?
= look at the bars and compare them to the reference/unknown
llll llll - Unknown
llll lll - Helium (yes)
lll - Hydrogen (no)
Red Shifted spectrum
- Further away / Shifting away from earth
= Longer / larger wavelengths & Lower frequency - Means the universe is expanding and is most commonly seen.
Blue Shifted Spectrum
- Closer / Shift towards earth
= Shorter wavelengths & Higher frequency - Means the universe is contrating and is not commonly seen
What do the different colour of stars mean?
Blue = Hot
Red = Cool
Motors vs Generators
Motors = Chemical potential -> Electrical -> Kinetic energy / spinning of armature
Generators = Kinetic energy -> Electrical energy
Induction
The process of generating current in a conductor by placing it in a changing magnetic field.
Picture of smpeter with a motor and how when the motor spins and interacts with the permanent magnet the current is generated.
