Physics quiz IV
Solenoid = Wrapping the wire around a piece of iron (shaped) more turns = stronger electromagnet & magnetic lines of force *The direction that the wire is coiled around the core also determines the direction of magnetic polarity.
An electrically charged coil of insulated wire, which produces a magnetic field within the coil. more turns = WHAT? direction of wire = WHAT?
The positive electrode is the electrode with a higher potential than the negative electrode. During discharge, the positive electrode is a cathode, and the negative electrode is an anode. During charge, the positive electrode is an anode, and the negative electrode is a cathode In an electrolytic cell the anode is positive because electrons flow from areas of high potential to low potent
Anodes and electrodes during charge and dicharge
True The reason this increases the capacitance is because it reduces the voltage between the capacitor plates their contribution to the voltage across the plates is being partially CANCELLED = due to polarization
By inserting an insulating material into a capacitor, there is increased capacitance = holds more charge and energy BUT has same amount of voltage. T or F
Spherical mirror = portion of sphere sliced w/ 1 reflecting surface CONCAVE = inwards - radius/Focus lies at FRONT of reflecting surface - Inverted (Real) BUT Magnified (Virtual) if close CONVEX = outwards - radius/Focus lies at BACK of reflecting surface - Virtual image, Reduced and Upright - give greater field of view
Concave vs Convex
Conductors = permits & easily transfers electrons (electric charge) Semiconductors = varying conductivity depending on impurities & charges present Insulators = CANNOT transfer electrons and do not permit movement of charge
Conductors vs Semiconductors vs Insulators
K = 9*10^9 Nm^2/C^2
Coulomb's constant
repel = positive (answers) attract = negative (answers)
Coulombs: If asking for the forces between a negative, positive and opposite charged particles, what are their signs?
Current is flow of electrons, but current and electron flow in the opposite direction. CURRENT = positive to negative ELECTRON = negative to positive. Current is determined by the number of electrons passing through a cross-section of a conductor in one second.
Current vs Electron flow?
Polarization
Division into two opposite charges within an object (negative and positive because of mass migration of electrons in a CONDUCTIVE material) (Disorientation in INSULATORS, wherein center is loss and with separation of charge, there is NOT an imbalance of charge.)
Yes. Polarization. polarization process always involves the use of a CHARGED OBJECT to induce electron movement or electron rearrangement.
Is it true that atoms are free to move from atom to atom within a conducting material but what causes this?
Note: Q1=C1V1 and Qt = CeqV Parallel V = V1 = V2 Q = Q1 + Q2 C = C1 + C2 Series V = V1 + V2 V = Q/C Q/C = Q/C1 + Q/C C = 1/C1 + 1/C2
Formula for Capacitors in a Series and Parallel
Fmg= ILB(sinθ) = qvB(sinθ) perpendicular = NO sineθ
Formula for Magnetic Force?
R = V/I (Ohms or V/A)
Formula for Resistance
Series: I = I1 = I2 = I3 V = V1 + V2 + V3 R = R1 + R2 + R3 Parallel: I = I1 + 12 + 13 V = V1 = V2 = V3 R = 1/R1 + 1/R2 + 1/R3
Formula for Series and Parallel circuits
B = µ*I*n where; n = turns (N)/ (L) length of wire (turns per meter)
Formula for finding B in a solenoid
C = ε0*A/d ε0=8.85*10^-12
Formula that expresses capacitance through dividing the area of each plate by distance between them and multiplying it by the constant of permittivity of free space?
Currents are made up of moving electric charges, and a magnetic field would exert a force on single electric charges that pass through it. = DEFLECTION
How does magnetic fields protect us from solar radiation
electric power
It is the rate at which electrical energy is converted to another form of energy
Ferromagnetism
The property that allows metal alloys to be attracted to magnets or are capable of being transformed into permanent magnets
Coulomb's Law (F=K q₁*q₂/r²) K = 9*10^9 Nm^2/C^2
The relationship among electrical force, charges, and distance: The electrical force between two point charges varies directly as the product of the charges and inversely as the square of the distance between them.
High voltage to low voltage
Voltage flows from?
-region where electrons are located - have varying density; greatest = highest prob of finding -e (Pagdi makita least dense) -highly distortable when obj with high -e affinity is present. (becomes asymmetrical (x centered) = polarized neutral atom) Insulators (-e disoriented) Conductors (-e movement)
What are electron clouds?
The more optically dense that a material is, the slower that a wave will move through the material
What does optically dense and speed have to do with each other?
OPPOSITE = attractive force SAME = repulsive force. T ↑charge ↑force ↑distance ↓force.
What happens between magnets with same and opposite charges? How about forces between them?
The lightbulbs would appear dim because ↑R↓I (less current) But Parallels, V is the same basta strong battery = strong current ↑I↓R Series: add resistors = Rt increases Parallel: add resistors = Rt decreases
What happens if I put 3 lightbulbs in a series and parallel circuit?
A positive charge loses electric potential energy as it moves from high potential to low potential and vice-versa. On the other hand, a negative charge gains electric potential energy as it moves from high to low potential and vice-versa.
What happens to the PEe of charges as it moves from different potentials?
Factors affect sound: Pressure =↑P ↑v temperature = ↓T ↓v diff mediums (diff densities) = closer particles-> faster sound *Underwater sound waves don't vibrate the ossicles bones in your inner ear & can't detect where comes from *SONAR = time it takes for sound to travel back from seabed is measured so depth can be acquired.
What happens when sound waves travel thru air and thru water? How about temperature? Why can't we pick up sounds underwater like we do above ground? Sonars and depth?
We know that circuits follow a PATH of LEAST RESISTANCE (resistance is from light bulb) SHORT CIRC: an electric current flows down the wrong or unintended path with little to no electrical resistance no current = no light from bulb
What happens when you have a short circuit on your light bulb project?
The direction of the current is always opposite the movement of negative charges, but a current can be generated by particles of either charge.
What is the direction of the current through the wires as compared to the direction of negative charges?
F=K q₁*q₂/r² F=8.99*10^9*1.6 x 10^-19/5^2 = 3.2*10^-30
What is the magnitude of the electric force bet. two protons five meters apart?
R = 1/10 + 1/10 = 2/10^-1 = 10/2 = 5 ohms *flip it kung same lang naman ng denominator
What is the total resistance of two resistors with 10ohms each in a parallel circuit?
Electric field strength (Kc*q/R^2)
The force per unit charge experienced by a small test charge placed in the field.
Higher temperature = high resistance Low temperature = less resistance (superconductor)
The higher the temperature of metals must have an effect on its resistivity. What happen if temp is increased?
Electromagnetism
The interaction between electricity and magnetism KASE electric current produces a magnetic field AND changing pattern of magnetism generates an electric current
True
The larger plates or the closer together, fits more charge thus a stronger electric field (= larger capacitance). T or F
free electrons
The outermost electrons (VALENCE) in the atom's orbit that can most easily be attracted away from the nucleus, when acted upon by an "outside force", resulting in flow of electric current.
Ampere's Law
The principle wherein an electric current generates a magnetic field that is proportional to the strength of the current. If the current is flowing in a coil of wire, the strength of the magnetic field is also proportional to the number of turns of wire in the coil.
Induction
The process of generating current in a conductor by placing the conductor in a changing magnetic field.
Volts
_______ are not a measure of energy, they are a measure of change in energy per unit charge.
(1) v = λf (wavelength*freq) = √Bulk modulus/density (2) v = 331 + 0.6T -T is celsius (3) v = c/n
(1) Wave speed formula; and for mediums? (2) speed of sound thru air (3) speed of light thru material (refraction)
(1) exhibit superposition & create interference patterns that will create resultant wave: *CONSTRUCTIVE (Same axis) = 2x the amplitude @ complete overlap *DESTRUCTIVE (diff axis) = amplitude is zero or less than original @ complete overlap [out of phase] (2) increase! = ↑v ↑λ Slower speed = shorter wavelength *frequency doesn't change w/ speed BUT ↓F ↑λ (3) 340 m/s
(1) When waves overlap what happens? Constructive vs Destructive? (2) As speed increases, does wavelength increase or decrease? (3) speed of sound in air @ 20C @ sea level?
electric motor
- A device that uses an electromagnet to turn an axle - converting electrical energy into mechanical energy
Equipotential lines
- designate the set of points around a source charge or multiple source charges that have the same electrical potential - always perpendicular to field lines - work is done when a charge is moved from one line to another - no work is done when a charge moves from one point on a line to another point on the same line
electromagnetic waves
- transverse waves consisting of changing electric fields and changing magnetic fields (E in Y direction = MG in Z direction) *perpendicular to each other and to the direction. - travels at speed of light and don't need media to propagate - carries energy and momentum that can be given to particles
1) east -west = current north - south = force Out of page (z direction) = magfield 2) Out of page (z direction) = force
1) If the current is in headed to east where is the force and magfield 2) current is north, and magfield is east
stronger the force (Fmg)!!
1)longer wires, 2) ↑current, ↑magnetic field (B), 3) closer to perpendicular the current is w/ respect to magfield direction 4) more charge the particle has 5) faster particle is moving
R = µ*I/2πB = 4π*10^-7(10A)/ 2π (8.0*10^-4) = 2.5*10^-3m or 2.5mm
A wire carries a current of 10A. At what distance from the wire will a magnetic field of 8.0*10^-4 be produced ?
CONVEX LENS 1) If parallel to PA, refraction passes thru F2 2) If goes str8 @ optical center, no deviation [diagonal lang siya] 3) If passes thru F1, refraction parallel to PA CONCAVE LENS 1) If parallel to PA, refraction came from F2 2) If goes str8 @ optical center, no deviation [diagonal lang siya] 3) If passes thru F1, refraction parallel to PA
3 rules for drawing ray diagrams for convex lenses? 3 rules for drawing ray diagrams for concave lenses?
*Yes. Same produced image but CONVEX LENS forms it on the opposite side. Convex LENS: O @ infinitely far = located at F; opp side Real image, Inverted, Reduced (parallel rays from distant object) Objects @ beyond C = located bet. C & F; opp side, Real image, Inverted, Reduced O positioned @ C = located at C at the opp side; real image - inverted - same size O positioned between C & F = located beyond C at the opp side; real image - inverted - enlarged - O positioned @ F = no image formed O positioned between F & P = located far at same side, Virtual, Upright, Magnified ________________ *YES! Same side naman nagform sa concave lens and the closer obj the bigger rin & mas malapit sa lens
A convex lens acts a lot like a concave mirror. T or F? Is the same true for convex mirrors and concave lenses?
Fmg= ILB (NOTE: F/L na kase N per meter!) Fmg/L= IB 0.75 = 35A*B =0.75/35 = .0214 T
A current of 35A flows due west in a wire that experiences a magnetic force of 0.75 N per meter. What is the strength of the magnetic field which is directed due south?
Plane mirror
A flat mirror that produces an upright, virtual image the same size as the object (never inverted but LATERALLY inverted; our L is image R)
E = F/q (dahil north magiging south (+) & convert microC to C) = 100N/20x10^-6 = 5*10^6 N/C
A force of 100N is directed north on a -20microC point charge. What is the magnitude and direction of the electric field at this point?
electricity
A form of energy caused by the movement of electrons. *stream of electrons trying to get from a negative place to a positive place
Resistance (R = V/I)
A material's opposition to the flow of electric current or charge. It depends on the composition and dimensions of a substance
Electrode
A metal part of an electrochemical cell, which gains or loses electrons. is a solid electric conductor that carries electric current into non-metallic solids, or liquids, or gases, or plasmas, or vacuums.
Photon
A particle of electromagnetic radiation with no mass that carries a quantum of energy carry the electrostatic force between the electron and the proton.
Fmg=qvB = (1.6*10^-19)(4 x 10^6)(2 x 10^-4) = 1.28 x 10^-16
A proton moves east with a speed of 4 x 10^6 m/s in a magnetic field of 2 x 10^-4 T directed into the page. What is the magnitude of the magnetic force acting on the proton?
N = n/L = 800/0.15m = 5333 turns/m B = µ*I*n = (4π*10^-7)*5*(5333) = 0.0335 T
A solenoid has a length of 15cm and a total of 800 turns of wire. Calculate the strength of the magnetic field at its center if the solenoid carries a current of 5.0A.
They reach the wall at the same time. Don't be fooled! The amplitude of a wave does not affect the speed at which the wave travels. Both Wave A and Wave B travel at the same speed. The speed of a wave is only altered by alterations in the properties of the medium through which it travels.
A teacher attaches a slinky to the wall and begins introducing pulses with different amplitudes (A=higher amp & B=lower amp). Which of the two pulses (A or B) below will travel from the hand to the wall in the least amount of time? Justify your answer.
Mechanical Wave
A traveling disturbance that transfers energy from place to place It is a kind that requires a medium through which to travel to (displacement of matter)
B = µ*I/2πR =4π*10^-7 (45A)/ 2π (0.02m) = 4.5 x 10^-4 T
A vertical wire carries a current of 45A due south. Calculate the magnitude and the direction of the magnetic field 2cm to the right of the wire
F = 1/2π√L*C λ = 2πc√L*C
Resonant frequency and wave from antenna of LC Circuits formula
Active = accept the electric flow Passive = restrict the flow
Active dielectrics vs Passive dielectrics
Air to glass -> bends toward the normal [for optically rarer to denser] Glass to air -> bends away from the normal [for optically denser to rarer] optically rarer = faster optically denser = slower
Air to glass -> bends toward what? Glass to air -> bends away from what?
B = µ*I/2πR R = µ*I/2πB
Ampere's Law equation
AMPLITUDE (A=H-L/2)= height of crest (taas) or through (baba) - higher = more energy - change in pressure raw sa soundwaves WAVELENGTH (λ=d/#cyc) = horizontal distance of crest-crest or through-trough (one cycle or oscillation) PERIOD (T=1/f or =time/cyc) = time it takes to complete a cycle FREQUENCY (f=1/T or =cyc/time) = number of waves that pass a point in a given time - HERTZ
Amplitude vs Wavelength vs Period vs Frequency
Triboelectric charging - the rubbing (friction) of two objects to create a charge (gains & loses) Induction charging - temporary electrical dipolar charged condition in 2 neutral object by causing a segregation of charges with a NEARBY source of charge. (after polarization; ends with each a positive & negative due to migration; DIFFERENT) Conduction charging - involves contact of a charged object to a neutral object (ends w/ SAME charged but less charge young hindi neutral) *not incontact - induction incontact = conduction
CHARGING: Triboelectric vs induction vs conduction
Electromagnet
COILING a current-carrying conductor around a core material that can be easily magnetized, such as iron, can form WHAT?
C=Q/V (farads) How much charge you can hold per volt (store charge in form of electrostatic field) C DONT depend on V Q depend on V
Capacitance and formula
Faraday's law of electromagnetic induction
Changing magnetic field = electromotive force in a wire (emf) induced e.m.f. is proportional to the rate of change of magnetic flux In other words, the faster the magnetic field changes, the greater the voltage in the circuit will be
True. Overall, the system of two objects has a net charge of 0 units. Ex. After the charging process, the more electron-loving object may acquire a charge of -12 units; the other object acquires a charge of +12 units
Charge is always conserved. True or False?
The Doppler effect occurs when on object that is emitting light is in motion with respect to the observer = The speed of light does not change, only the wavelength = If the object is moving TOWARDS the observer the light is "COMPRESSED'' or BLUESHIFTED = If the object is moving AWAY from the observer the light is "EXPANDED'' or REDSHIFTED
Doppler Effect FOR LIGHT?
Antenna
EM waves produced with a conductor - the length of ____ is half the generated wavelength - metallic conductors that encounter these waves produce and induce current that be monitored or translated into usable info (radiowaves from tv & cellphones)
1.6 x 10^-19 coulombs electrons (-e); protons (+e) -1C = 6.25 X 10^18 electrons
Each electron carries with it the fundamental charge, which is? How about 1 Coulomb is the total charge carried by how many electrons?
TRUE! the shape, and resulting strength, of an electric field, are dependent on the number and position of the electric charges. each point in space can be assigned a vector to determine the direction and magnitude of motion
Electric field stregth is dependent on the number and position of the electric charges, is this true? Does each point in space determine the direction and magnitude of motion?
electric field = electric force per unit charge; measurable effect created by charged object Charged object = a surrounding electric field Interactions = charged object enters an electric field (2 charged objects) Elec Field Lines: (-) Points TOWARDS (+) Points AWAY Properties: (1) Field lines must be tangent to direction of field at any point (2) More lines (↑dense) = stronger field (↑magnitude) (3) Start in positively charged and end on negatively charged (4) lines never cross
Electric fields, its lines and their interactions?
∆PE = -qEd -q = opposite of obj charge E = electric field strength
Electrical Potential Energy in a Uniform Electric formula
Once these free charges are at equilibrium, their acceleration is zero, which means that there are no longer any net forces acting on them. acceleration = 0 net force = 0 electric field = 0
Electrostatic equilibrium
Light wave
Energy is only being transferred by waves and not the medium itself. Some waves don't require a medium. What is this?
Closer to negative (low potential & low voltage) Positive = high potential & high voltage
Equipotential lines run parallel to the plates of capacitors, and each line that's closer to the negative plate has ____ electric potential and _____ voltage
From longest wavelength to shortest: AM, Radiowaves, Microwave, Infrared, Visible, Ultraviolet, X-ray, Gamma ray Long Wavelength= Low Energy & Freq Short Wavelength= High Energy &Freq
Explain: A Raging Martian Invaded Venus Using X-ray Guns Where does energy increase and wavelength decrease?
Emf = -n*change in flux/change in time
Faraday's Law equation
EMF = n * Δ Φm/t where; n = # of turns Δ Φm = magnetic flux
Faradays's Law equation
thumb, forefinger and middle finger of the right-hand perpendicular to each other thumb points towards the direction of the magnetic force, the forefinger points towards the direction of the magnetic field and the middle finger points towards the direction of the current. grip rule = thumb current; fingers mag field 1) all fingers + fold = thumb force, fingers magfield; palm current 2) all fingers + fold 2 upwards = thumb force (+ = thumb; (-) = opp thumb), fingers magfield; palm q velocity Curr towards you = counterclockwise magfiels
How does one use the right hand rule to determine the direction of the force applied to a current carrying wire? vs grip rule vs right hand all fingers
ELECTROSTATIC DISCHARGE (1) Static Charge Buildup in the Clouds (2) ↑static charge + ↑electric field surrounding clouds = ionized air (+p & free -e ) ready to transfer -e (3) Clouds strikes (disoriented) positively charged ground to transfer -e = neutralized cloud *air cannot serve as insulator anymore KASE strong electric fields surrounding a cloud IONIZES surrounding air = more conductive
How is lightning created by the clouds? Is this truly a product of electrostatic forces?
∆V = ∆PE/q 12V = ∆PE/3.0 C ∆PE = 36
If 3.0C of charge move through a 12V potential difference, what is the change in electric potential energy?
d=vt; halved time for 1-way distance = (340)(.075) = 25.5m
If a sound wave (speed = 340 m/s) returns to the camera 0.150 seconds after leaving the camera, then how far away is the object?
magflux decrease = increases EMF magflux increases = decreases EMF
If the magnetic flux through a loop of wire decreases over time, the emf _______ accordingly. And if the flux increases over time, the emf decreases.
(A) O positioned infinitely far = located at F = highly diminished (smallest), Virtual, Upright (B) O positioned bet. infinity & pole = bet P & F = Virtual, Upright , & Reduced * as OBJECT gets closer to MIRROR it ENLARGES but never bigger than actual object
Images Formed by Concave Mirrors Objects: (A) O positioned infinitely far (B) O positioned between infinity & pole (finite distance)
O @ infinitely far = located at F; same side Real image, Inverted, Reduced (parallel rays from distant object) Objects @ beyond C = located bet. C & F; same side, Real image, Inverted, Reduced O positioned @ C - real image - inverted - same size - located at C at the same side O positioned between C & F = real image - inverted - enlarged - located beyond C at the same side O positioned @ F = no image formed O positioned between F & P = located far at opposite side, Virtual, Upright, Magnified
Images Formed by Concave Mirrors Objects: (A) O positioned infinitely far (B) O positioned beyond C (C) O positioned at C (D) O positioned between C & F (E) O positioned at F (F) O positioned between F & P
There are three types of spectra emitted by objects: Continuous spectrum - a solid or liquid body radiates an uninterrupted, smooth spectrum (Planck curve) Emission spectrum - a radiating gas produces a spectrum of discrete spectral lines Absorption spectrum - a continuous spectrum that passes through a cool gas has specific spectral lines removed (inverse of an emission spectrum)
In Kirchhoff's Laws, there are three types of spectra emitted by objects:
True. As charged particles move within an electric field their electrical potential energy changes.
In electrical fields, it is the field that does the WORK to produce the acceleration. True or false?
Inductance and capacitance Oscillating - kase capacitor discharges and once max is reached, magfield collapses the current weakens thus inductor releases energy to sustain the current.
LC circuits consist of a(n) _____ and a(n) _____ connected in series or in parallel with a voltage source. LC circuits produces _________ waves or current
TRUE! large electric fields create free charges (electrons in this case) that are able to move freely through the material and carry current. This process is called dielectric breakdown because the dielectric transitions from being an insulator to a conductor = spark and damage to the capacitor.
Large electric fields ionize the atoms of a dielectric and lead to Dielectric breakdown?
LAW OF REFLECTION: angle of incidence = angle of reflection (incident, reflected & normal lie in same plane) LAW OF REFRACTION: n1sinθ1 = n2sinθ2 (incident, refracted & normal lie in same plane @ pt of incidence) n = speed of light in incident / speed of light in refractive = v1/v2 = c/v If n2 > n1, then θ2 < θ1; θ is always a measure of the angle from the normal. TOTAL INTERNAL REFLECTION: high to low n
Law of reflection vs Law of Refraction vs Total internal reflection Give their formulas
LENS equation (1/f = 1/do + 1/di) where; i = image position & o = obj position MAGNIFICATION (m = hi/ho = -di/do) where; hi = image height & ho = obj height _______________________ Right of mirror = Positive Left = negative (OBJECT always negative) Above PA = Positive Below PA = negative
Lens equation and Magnification Formula
Sound waves
Longitudinal waves initiated through vibration and requires a medium to travel through. (Compressions & change in pressure) - this can't travel in vacuum or space. - depends on medium (gas is slowest & solid fastest)
1) a magnetic field in the surrounding space a moving charge or a current creates 2) the magnetic field exerts a force F on any other moving charge or current that is present in the field
Magnetic Interactions can be described in two steps:
NORMAL = converging @ retina MYOPIC (near) = converging @ front of retina - CONCAVE LENS (cause diverge= @ retina na) - that's why hazy ang distant objects - DUE 2 high converging power & long eyeball - NEGATIVE focal length HYPERMETROPIA (Far) = converging behind retina (more than normal near point) - CONVEX LENS (cause converge= @ retina na) - DUE 2 low converging power & short eyeball + weak ciliary muscles - POSITIVE focal length _____________ Near pt = closes distance for eye focus (25cm) Far pt = farthest distance for eye focus (∞) ------------------- Bifocal lenses = both far and nearsighted
Myopic vs Hypermetropia Near vs Far point?
PITCH = highness or lowness depends on frequency (↑PITCH ↑f) - ultrasonic = too high; infrasonic = too low INTENSITY = loudness depend on amplitude (Power/Area) Doppler effect = source closer -> intensity & pitch increases so higher frequency than MALAYO Nodes = zero amplitude Antinodes = max amplitude
Pitch vs Intensity vs Doppler effect Nodes vs antinodes
POLE (P) or Vertex - center point of reflecting surface CENTER (C)- center of the spherical mirror from where the radius originates PRINICIPAL AXIS - a line passing through the center of the mirror RADIUS of curvature - from Center to P FOCUS (F)- point on the principal axis that is halfway between the mirror and the center Focal Length - distance between the mirror and the focus; half the length of the radius
Pole vs Center vs Principal axis vs Radius vs Focus vs Focal length
primary coil = AC current is fed in. secondary coil = current is induced to perform some sort of transfer of energy *Both coils in a transformer are affected by each other's induced magnetic fields.
Primary vs Secondary coil
REFLECTION = bounces off (ex. Mirror, metal & echos) TRANSMISSION = same direction (ex. Glass window-sunlight) REFRACTION = change in direction & speed due to diff densities of media (furnished room-lesss-sound & water-appears-shallow; bent-straw) = Specular (smooth) & Diffuse (rough) DIFFRACTION = pass thru gap & scatter depends on gap. (Clouds-light & holograms) while SCATTERING = all directions (blue-sky-of-sunlight) POLARIZATION = only in one direction; filtered
Reflection vs Transmission vs Refraction vs Dispersion vs Diffraction vs Polarization
Simple: curved & curved or plane [2 sides] BICONVEX = bend light TOWARDS each other BICONCAVE = bend light AWAY each other PLANOCONVEX = plane on one side PLANOCONCAVE = plane on one side MENISCUS = both concave & convex (- = ↑C)
Simple lens provide its types and image formed.
CURRENT (FLOWS) electricity is generated by the passage of electrons down a conductor, whereas STATIC (GATHER) electricity is caused by the accumulation of electrical charges on the surface of things. When objects are rubbed together, electrons are lost and/or gained, resulting in the condition of static electricity.
Static vs. Current Electricity
Opposite So if accelerates/force is east = e field is west
The direction of the force and electric field is always ______ to each other?
perpendicular
The direction of the force from a magnetic field on a current running through a wire will be _______ to both the magnetic field and the current.
Lenz's Law
The direction of the induced e.m.f. or current is always such as to oppose the change producing it. magnetic field generated by the induced current will be in the direction opposite the change magnetic flux
True
The farther away from a point charge, the lower the voltage. True or False
They reach the wall at the same time. Don't be fooled! The wavelength of a wave does not affect the speed at which the wave travels. Both Wave C and Wave D travel at the same speed. The speed of a wave is only altered by alterations in the properties of the medium through which it travels.
The teacher then begins introducing pulses with a different wavelength. Which of the two pulses (C-longer or D-shorter) will travel from the hand to the wall in the least amount of time ? Justify your answer.
Remember t=d/v so 20/340 = 0.059s
The time required for the sound waves (v = 340 m/s) to travel from the tuning fork to point A @ 20m is ____ .
If the wave travels 2.5 meters in one second then it will travel 5.0 meters in 2.0 seconds. If Wilbert gets drenched every time the wave has traveled 5.0 meters, then he will get drenched every 2.0 seconds.
The water waves below are traveling along the surface of the ocean at a speed of 2.5 m/s and splashing periodically against Wilbert's perch. Each adjacent crest is 5 meters apart. The crests splash Wilbert's feet upon reaching his perch. How much time passes between each successive drenching? Answer and explain using complete sentences.
TRANSVERSE = perpendicular Ex. Electromagnetic & ocean waves LONGITUDINAL = parallel (thru compression - push or rarefaction - pull) ex. Sound LINEAR = amplitude is much less than the wavelength and the wavelength much greater than the depth RADIAL = circular
Transverse vs Longitudinal vs Linear vs Radial waves
c. neutral Overall, the two cans are neutral; yet as individual cans, Can X is negatively charged and Can Y is positively charged. When the cans are touched again, the excess electrons in Can Y return to Can X. Once more, the overall charge on the system of two cans is zero - the system is neutral.
Two neutral conducting pop cans are touching each other. A positively charged balloon is brought near one of the cans as shown below. The cans are separated while the balloon is nearby, as shown. After the balloon is removed the cans are brought back together. When touching again, can X is ____. a. positively charged b. negatively charged c. neutral d. impossible to tell
same direction = attracted opposite direction = repelled
Two parallel wires has a current running in the same direction, the wires will then be _____ to each other. And when you ran a current through both wires in the opposite directions, the wires ______ each other?
C. Same as The medium is the same for both of these waves ("the same container of nitrogen gas"). Thus, the speed of the wave will be the same. Alterations in a property of a wave (such as wavelength) will not affect the speed of the wave. Two different waves travel with the same speed when present in the same medium.
Two waves are traveling through the same container of nitrogen gas. Wave A has a wavelength of 1.5 m. Wave B has a wavelength of 4.5 m. The speed of wave B must be ________ the speed of wave A. (A) one-ninth (B) one-third (C) same as (D) three times larger
VIRTUAL: an image that forms when the light rays DIVERGE after reflecting from the mirror. - diverges behind so appears BEHIND (Plane mirror), UPRIGHT - imaginary intersection of light ray. - formed by perception; illusory effect formed by the brain's assumption that light always travels a straight line; CANNOT be captured by a projection screen REAL: an image that forms when the light rays INTERSECT (diverge same side) after reflecting from the mirror. - formed on SAME side (concave), INVERTED -image formed by actual light; can be captured by a PROJECTION SCREEN
Virtual vs Real image
Changing mediums lead to a change in speed! therefore the direction changes as well. Speed still changes. However, when it is PERPENDICULAR it doesn't bend and travels in the same direction as incident ray. REFRACTION depends on medium
When light enters a medium at an angle and refracts, it changes its direction. Why does this happen? What if light enters perpendicular to the surface? Will its speed change and will it refract?
Electrons from one plate is moved to the other plate. The one that lost -e is (+) and the one that gained -e is (-). No. Same positive charge on (+)plate as there is negative charge on (-) plate KASE battery uses its own eectric potential to make current transfer voltage to the capacitor, so capacitor gains potential energy
When you connect a capacitor to a wire and a battery, what happens to the charges of each capacitor plate? How about net charge gained? Does it change?
between the capacitor plates = electric field OR dielectric
Where is the electric charge stored in a capacitor
The long wire has more resistance kase based sa formula si L ang numerator. More space for electrons to move sa thick so less resistance. ↑L↑R ↑A↓R
Which has higher resistance a long wire vs a short wire? How about a thin vs thick wire?
Because of the different indices of refraction for the different wavelengths of visible light, the angle of deviation varies with wavelength. Colors of the visible light spectrum that have shorter wavelengths (BIV) will deviated more from their original path than the colors with longer wavelengths (ROY). Violet light, being slowed down to a greater extent by the absorption and re-emission process, refracts more than red light. Blue light refracts more or deviates more so it has a greater angle of deviation than red light
Which refracts more BIV or ROY? And who is slower?
The constant churning of the molten iron in the Earth's outer core creates electrical currents and those currents generate the Earth magnetic field. Addtl: it protects our planet from cosmic radiation and from the charged particles emitted by our Sun
Why does earth have its own magnetic field that helps in navigating north & south?
Both are insulators (resist flow of electric charges) Consequently, when you rub a balloon on wool, this causes the electrons to move from the wool to the balloon's surface. (Center is lost and electrons shift around) Rubber > Wool RUBBER (↑-e affinity) = gains e & (-) WOOL (↓-e affinity) = loses & (+) SAME NUMBER PARIN OF E kase NEUTRAL sila polythene > Wool When neutral objects become polarized, they are still neutral objects.
Why does wool and rubber create static electricity? Which becomes partially positively charged and negatively charged? How about a polythene piece and wool?
materials contain paired electrons in orbitals that CANCEL each other out BUT Iron, nickel & cobalt have UNPAIRED electrons that DON't cancel out *ferromagnetism = align in parallel (magnetic domain) = magnetic field
Why is some materials ferromagnetic?
Winter = risen hot air refract sound down. Snow absorbs sound so muffling effect. SAME @ Night Summer = hot air on ground & cooler above so sound refract upward. Humid (↓density) & ↑T = faster sound
Why is sound louder during winter than in the summer?
Kirchhoff's Law of Current and Voltage
[circuits] 1. the sum of current flowing into a junction must equal the sum of the current leaving at any junction, and 2. the sum of voltage sources = the sum of voltage drops around a closed-circuit loop The energy that flows into the circuit must equal the energy that comes out of that circuit
Circuits *Energy source - makes current move *Load - converts elec to another form (light energy) *Wires - Connect *Switch - close/open
a complete, closed path through which electric charges flow state its parts too.
defibrillator It shocks the heart (enough potential energy to stop) to stop irregular heartbeat. It gains potential energy that is converted to electricity.
a device that delivers an electric shock to the heart to restore its normal rhythm. Explain.
transformer
a device that increases or decreases the voltage of an alternating current a device that transforms electricity form one voltage to another and has two windings or coils. One is called the primary, the other the secondary
Capacitor
a device used to store an electric charge, consisting of one or more pairs (opposite charges) of conductors separated by an insulator (dielectric). It creates a uniform electric field = Fe is constant, and it acts in the direction in which test charge moves
electromagnetic radiation
a kind of radiation including visible light, radio waves, gamma rays, and X-rays, in which electric and magnetic fields vary simultaneously. a form of energy that exhibits wavelike behavior as it travels through space
Dielectric
a medium or substance that transmits electric force without conduction; an insulator. An insulating material placed between the two plates of a capacitor, allowing for the storing of more charge (if the circuit is on) or a decrease in the voltage difference (if the circuit is off). This increases the capacitance of two plates and prevents electrons from crossing the gap BUT decreases the electric field inside the capacitor - has polarized molecules
magnetic field
a region around a magnetic material or a moving electric charge within which the force of magnetism acts.
Voltaic cell (galvanic cell)
an electrochemical cell in which a spontaneous reaction generates an electric current
magnet
any material that attracts iron and materials that contain iron It has maximum attraction at its poles and minimum at the center
*SINE Theta @ 90deg = current is perpendicular to the magnetic field lines = 1 = strongest *SINE Theta @ 0deg = current is parallel to the magnetic field lines = 0 = NO FORCE on wire
current perpendicular vs parallel to the magnetic field lines
Maxwell's Equations
describe the electric and magnetic fields arising from distributions of electric charges and currents, and how those fields change in time.
electric = opposite charges can be isolated magnets = always contains both poles
electric charges vs magnets
I = Q/t (ampere or C/s)
electric current formula
E = Fe/q = kQ/r^2 where Q = source charge q = test charge
electric field formula
P = IV = I^2R = V^2/R (Watts)
electric power formula
compasses
instruments for showing directions, having a needle that always points geographic north follows magnetic field lines of earth
a region around a magnetic material or a moving electric charge within which the force of magnetism acts. begin = the north pole = AWAY end = south pole, = TOWARDS *NO true ends
magnetic field lines
Δ Φm = BLw = BAcosθ
magnetic flux equation
decrease, increase ↑R ↓B ↑I ↑B
move away from the wire = ____ strength of magfield increase electric current = ____ strength of magfield
Static electricity
occurs when an object obtains a net amount of positive or negative electric charge, creating an imbalance that wants to be returned to equilibrium generated by friction between two insulating materials. Wherein, both neutrally charged objects start to shift electrons and lose their center due to overlapping electron clouds (disoriented lang; transfer?) object with higher electron affinity attracts -e -> partially negative charge
R=p*L/A
resistance of a wire = formula
Series: The current through each of the components is the same, and the voltage across the circuit is the sum of the voltages across each component. Parallel: Two or more paths for current to flow through. Voltage is the same across each component of the parallel circuit. The sum of the current through each path is equal to the total current that flows from the source.
series circuit vs parallel circuit
ground
serve as a supplier or receiver of electrons simply a large object that serves as an almost infinite source of electrons or sink for electrons *(if in contact with an object that needs to transfer/receive -e kase may isa pang charged object)
Ohm's Law (V=IR)
the current in a circuit equals the voltage difference divided by the resistance ↑V↑I ↑R↓I
potential difference (∆Volts = ∆PEe/q OR V = -Ed)
the difference of electrical potential between two points in a field It equals the work that must be performed against electric forces to move a charge between the two points in question, divided by the charge.
magnetic force
the force of attraction or repulsion generated by moving or spinning electric charges
electromotive force (emf)
the force that results in the motion of electrons due to a difference in potential, forming a current
a) galvanometer & d) ammeter = current b) voltmeter = voltage c) ohmeter = resistance Note: - Galvanometers and ammeters are always connected in series with a resistor. - Voltmeters are always connected in parallel with the resistors. - Ohmmeter is used by disassembling first the resistor from the circuit before measuring its resistance.
which measures current, voltage and resistance in these devices? a) galvanometer b) voltmeter c) ohmeter d) Ammeter
