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First Sergeant
Join Date: Feb 2011
Posts: 150
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electric field lines do not intersect
comprehensive physical formula super! ! ! Useful to say ~ ~ ~ (according to the order of our physics lessons) -
1) uniform speed linear motion -
1. the average speed V flat = s / t (defined) 2. a useful corollary Vt2-Vo2 = 2as -
3. middle of the speed Vt / 2 = V flat = (Vt + Vo) / 2 4. terminal velocity Vt = Vo + at -
5. the middle position, velocity Vs / 2 = [(Vo2 + Vt2) / 2] 1 / 2 6. displacement s = V level t = Vot + at2 / 2 = Vt/2t -
7. acceleration a = (Vt-Vo) / t {to Vo as the positive direction, a and Vo in the same direction (acceleration) a> 0; back then a
5. cycle and frequency: T = 1 / f 6. the relationship between angular velocity and linear velocity: V = ωr -
7. the relationship between angular velocity and rotational speed ω = 2πn (here meaning the same frequency and speed) -
3) gravity -
1. Kepler's third law: T2/R3 = K (= 4π2/GM) {R: orbital radius, T: period, K: constant (nothing to do with the planet's mass, depending on the quality of the central body)} -
2. law of universal gravitation: F = Gm1m2/r2 (G = 6.67 × 10-11N? m2/kg2, the direction in which the connection) -
3. celestial body gravity and the acceleration of gravity: GMm/R2 = mg; g = GM/R2 {R: object radius (m), M: celestial body mass (kg)} -
4. satellite orbiting speed, angular velocity, cycle: V = (GM / r) 1 / 2; ω = (GM/r3) 1 / 2; T = 2π (r3/GM) 1 / 2 {M: central body mass} -
5. The first (second, third) speed of the universe V1 = (g to r to) 1 / 2 = (GM / r in) 1 / 2 = 7.9km / s; V2 = 11.2km / s; V3 = 16.7km / s -
6. geostationary satellite GMm / (r to + h) 2 = m4π2 (r to + h) / T2 {h ≈ 36000km, h: the height from the Earth's surface, r to: the radius of the Earth} - / p>
Note: -
(1) the centripetal force required for movement of celestial objects provided by the gravitation, F = F million to; -
(2) application of the law of gravity can estimate the object's mass and density; -
(3) Geostationary satellites can only run on the equator, running the same cycle and Earth's rotation period; -
(4) satellite orbital radius decreases, smaller potential energy, kinetic energy becomes larger, the speed becomes larger, the cycle becomes smaller (with three anti-); -
(5) surround the Earth's largest satellite launch speed and minimum speed are 7.9km / s. -
1) common power -
1. gravity G = mg (the direction of straight down, g = 9.8m/s2 ≈ 10m/s2, the role of point in the center of gravity for the Earth's surface around) -
2. Hooke's Law F = kx {direction along the direction of recovery deformation, k: stiffness (N / m), x: type variable (m)} -
3. sliding friction force F = μFN {relative motion in the opposite direction and the object, μ: friction coefficient, FN: positive pressure (N)} -
4. Static Static friction 0 ≤ f ≤ fm (objects in relative motion with trend in the opposite direction, fm is the maximum static friction) -
5. gravitation F = Gm1m2/r2 (G = 6.67 × 10-11N? m2/kg2, the direction in which the connection) -
6. Static Electricity F = kQ1Q2/r2 (k = 9.0 × 109N? m2/C2, the direction in which the connection) -
7. electric force F = Eq (E: field strength N / C, q: charge C, is charged by the electric force and field strength in the same direction) -
8. Ampere force F = BILsinθ (θ is the angle between B and L, the time when the L ⊥ B: F = BIL, B / / L time: F = 0) -
9. Lorentz force f = qVBsinθ (θ is the angle between B and V, the time when the V ⊥ B: f = qVB, V / / B Time: f = 0) -
2) force composition and decomposition -
1. the same line with the composition of forces: F = F1 + F2, reverse: F = F1-F2 (F1> F2) -
2. each angled composition of forces: -
F = (F12 + F22 +2 F1F2cosα) 1 / 2 (cosine law) F1 ⊥ F2 time: F = (F12 + F22) 1 / 2 -
3. force size range: | F1-F2 | ≤ F ≤ | F1 + F2 | -
4. force orthogonal decomposition: Fx = Fcosβ, Fy = Fsinβ (β together with the x-axis is the angle between the tgβ = Fy / Fx) -
four, dynamics (motion and force) -
1. Newton's first law of motion (inertia): objects with inertia, keeping the total state of uniform linear motion or rest until the external force it to change this state so far -
2. Newton's second law of motion: F = ma or a co-co-a = F / ma {determined by a force, force direction and cooperation} -
3. Newton's third law of motion: F =- F '{negative sign indicates the opposite direction, F, F' respective roles in each other, balance, and reaction force difference between the actual application: recoil motion} -
4. a total balance of the point force F co = 0, the promotion of {orthogonal decomposition, the three forces intersect principle} -
5. Overweight: FN> G, weightlessness: FN > r} -
3. forced vibration characteristics: f = f driver -
4. resonance conditions: f = f solid driving force, A = max, to prevent resonance and application -
6. velocity v = s / t = λf = λ / T {wave propagation process, a cycle of forward propagation of a wave; velocity size is determined by the media itself} -
7. acoustic wave velocity (in air) 0 ℃: 332m / s; 20 ℃: 344m / s; 30 ℃: 349m / s; (Sound waves are longitudinal waves) -
8. wave obvious diffraction (wave continues to spread around obstacles or holes) conditions: the size of obstructions or holes smaller than the wavelength or less the same -
9. wave interference conditions: the same two wave frequency (a difference of constant amplitude similar vibration in the same direction) -
Note: -
(1) the natural frequency and amplitude objects, driving force independent of frequency, depending on the vibration of the system itself; -
(2) the vibration wave propagation only, the medium itself does not move with wave occurs, is a form of energy transfer; -
(3) is the Potter, some interference and diffraction; -
1. Momentum: p = mv {p: momentum (kg / s), m: mass (kg), v: velocity (m / s), direction and speed in the same direction} -
3. Impulse: I = Ft {I: Impulse (N? s), F: Constant (N), t: the role of force time (s), the direction determined by the F} -
4. momentum theorem: I = Δp or Ft = mvtmvo {Δp: change in momentum Δp = mvtmvo, is a vector-type} -
5. momentum conservation law: p = p after the former general, or p = p''can also be m1v1 + m2v2 = m1v1 '+ m2v2' -
6. elastic collision: Δp = 0; ΔEk = 0 {the system momentum and kinetic energy are conserved} -
7. non-elastic collision Δp = 0; 0
2. gravity acting: Wab = mghab {m: the mass, g = 9.8m/s2 ≈ 10m/s2, hab: a and b the height difference (hab = ha-hb)} -
3. electric force acting: Wab = qUab {q: charge (C), Uab: a and b between the potential difference (V) that Uab = φa-φb} -
4. Electric power: W = UIt (universal type) {U: voltage (V), I: current (A), t: power-on time (s)} -
5. Power: P = W / t (defined type) {P: power [watts (W)], W: t time, the work done (J), t: time spent doing work (s)} - ;
6. vehicle traction power: P = Fv; P level = Fv level {P: instantaneous power, P level: average power} -
7. car to start the constant power to constant acceleration start, car maximum speed (vmax = P Amount / f) -
8. Electric power: P = UI (universal type) {U: circuit voltage (V), I: circuit current (A)} -
9. Joule's law: Q = I2Rt {Q: electric (J), I: current intensity (A), R: resistance value (Ω), t: power-on time (s)} -
10. pure resistance circuit, I = U / R; P = UI = U2 / R = I2R; Q = W = UIt = U2t / R = I2Rt -
11. kinetic energy: Ek = mv2 / 2 {Ek: kinetic energy (J), m: body mass (kg), v: instantaneous velocity of the object (m / s)} -
12. gravitational potential energy: EP = mgh {EP: gravitational potential energy (J), g: acceleration due to gravity, h: vertical height (m) (starting from zero potential energy surface)} -
13. electrical potential energy: EA = qφA {EA: A charged body at the point of electric potential energy (J), q: charge (C), φA: A point of potential (V) (starting from zero potential energy surface)} -
14. kinetic energy theorem (to do positive work on the object, the object's kinetic energy increases): -
W or W co = mvt2/2-mvo2/2 co = ΔEK -
{W together: the total force on the object to do work, ΔEK: kinetic energy ΔEK = (mvt2/2-mvo2/2)} -
15. mechanical energy conservation law: ΔE = 0 or EK1 + EP1 = EK2 + EP2 also can be mv12 / 2 + mgh1 = mv22 / 2 + mgh2 -
16. gravity acting with the changes in gravitational potential energy (gravity acting is equal to the negative incremental gravitational potential energy of the object) WG =- ΔEP -
Note: -
(1) power level, said the speed of doing work, doing work that energy into the number of how many; -
(2) O0 ≤ α
(3) gravity (elastic, electric force, molecular force) to do positive work, the gravity (elastic, electric, molecular) potential reduction -
(4) electric force of gravity acting and acting are nothing to do with the path (see 2,3-two-type); (5) the establishment of conditions of conservation of mechanical energy: In addition to gravity (elastic) forces do no work outside the other, but between kinetic and potential energy conversion; (6) can be converted to other units: 1kWh (degrees) = 3.6 × 106J, 1eV = 1.60 × 10-19J; * (7) spring elastic potential energy E = kx2 / 2, and the stiffness and deformation on . -
eight, molecular kinetic theory, energy conservation -
1. Avogadro constant NA = 6.02 × 1023/mol; molecular diameter of magnitude 10-10 m -
2. film method to measure molecular diameter d = V / s {V: volume of single-molecule film (m3), S: film surface area (m) 2} -
3. Molecular Kinetic Theory of Content: the material is composed of large molecules; a large number of molecular thermal motion of no rule to do; interaction between the molecules. -
4. intermolecular attraction and repulsion (1) r r0, f cited> f exclusion, F molecular force performance of gravity -
(4) r> 10r0, f = f cited exclusion ≈ 0, F molecular force ≈ 0, E potential energy ≈ 0 -
5. thermodynamics first law of W + Q = ΔU {(acting and heat transfer, both within the object can change the way, in effect, is equivalent), -
W: external positive work done on the object (J), Q: heat absorbed by the object (J), ΔU: the increase in internal energy (J), relating to the first perpetual motion machine can not create - p>
7. Third Law of Thermodynamics: Thermodynamics zero temperature limit is not reached {the universe: -273.15 degrees Celsius (thermodynamic zero)} -
Note: -
(1) Brownian particle is not a molecule, Brown, the smaller the particles, Brownian motion, the more obvious the higher the temperature the more intense; -
(2) temperature is the average kinetic energy of molecular mark; -
3) attraction and repulsion between molecules exist, with the intermolecular distance decreases, but the repulsive force decreases faster than gravity; -
(4) molecular force does positive work, the molecular potential energy decreases, cited in F = F r0 at the exclusion and the potential energy minimum; -
(5) gas expansion, the outside world to do negative work on the gas W 0; absorb heat, Q> 0 -
(6) the internal energy of the object is the object of all the elements the sum of kinetic and potential energy, intermolecular forces for the ideal gas is zero, potential energy is zero; -
(7) r0 for the molecule in the equilibrium state, the distance between molecules; -
ten, the electric field -
1. two kinds of charge, charge conservation law, per charge: (e = 1.60 × 10-19C); charged body charge equal to an integer multiple of per charge -
2. Coulomb's Law: F = kQ1Q2/r2 (in vacuum) {F: the force between point charges (N), k: electrostatic constant k = 9.0 × 109N? m2/C2, Q1, Q2: two o'clock charge of electricity (C), r: the distance between two o'clock charge (m), the direction in which the connection, action and reaction, like charges repel each other, and dissimilar charges attract each other} - / p>
3. electric field: E = F / q (defined type, formula) {E: electric field strength (N / C), is the vector (electric field superposition principle), q: charge the battery test (C)} -
4. vacuum point (source) to form the electric field charge E = kQ/r2 {r: source charge to the location of the distance (m), Q: charge of the power source} -
5. uniform electric field of the field strength E = UAB / d {UAB: AB between two voltage (V), d: AB the distance between two points in the direction of the field intensity (m)} -
6. electric force: F = qE {F: electric force (N), q: charge by the electric force of electricity (C), E: electric field strength (N / C)} -
7. electric potential and potential difference: UAB = φA-φB, UAB = WAB / q =- ΔEAB / q -
8. electric force acting: WAB = qUAB = Eqd {WAB: A to B by a charged body electric force when the work done (J), q: with charge (C), UAB: the electric field in the A, B two potential difference between points (V) (electric force acting path independent), E: uniform electric field strength, d: two o'clock the distance along the field direction (m)} -
9. electrical potential energy: EA = qφA {EA: A charged body at the point of electric potential energy (J), q: charge (C), φA: A point of potential (V)} -
10. electrical potential changes in ΔEAB = EB-EA {charged body position in the electric field from A to B position, electrical potential difference} -
11. electric force acting with the electric potential energy ΔEAB =- WAB =- qUAB (the incremental electric potential energy is equal to the electric force acting in the negative) -
12. capacitance C = Q / U (defined type, formula) {C: capacitance (F), Q: charge (C), U: voltage (potential difference between two plates) (V)} -
13. parallel plate capacitor C = εS/4πkd (S: two plates are on the area, d: vertical distance between two plates, ω: k) -
14. charged particles accelerated in an electric field (Vo = 0): W = ΔEK or qU = mVt2 / 2, Vt = (2qU / m) 1 / 2 -
15. charged particles along the direction perpendicular to the electric field in order to speed Vo into the deflection when the uniform electric field (not considering the case of gravity) -
class flat vertical electric field direction: CV L = Vot (heterogeneous in charge with the same amount in the parallel plates: E = U / d) -
projectile motion parallel to the direction of electric field: initial velocity of zero uniformly accelerated linear motion d = at2 / 2, a = F / m = qE / m -
Note: -
(1) two identical charged metal ball contact, the power distribution law: first, the original tapes and in heterogeneous charge after the split, the original charge with the same amount of split; -
(2) electric field line starting from the termination of the positive charge on the negative charge, electric field lines do not intersect, the tangent direction to the direction of field strength, electric field line density at the field strength along the field lines becoming less and less electric potential, electric field lines and so on potential vertically; -
(3) common requirements of the electric field distribution of the electric field lines memorized 〔Figure [Volume P98]; -
(4) electric field (vector) and the electric potential (scalar) determined by the electric field itself, while the electric force and electric potential energy also charged body with the power and charge the number of positive and negative about; -
(5) in the electrostatic potential of Conductor is a body such as the surface is equipotential surface, the outer surface of the conductor near the surface of the electric field lines perpendicular to the conductor, conductor internal compliance field is zero, no net charge inside the conductor, the net charge only located in the outer surface of the conductor; -
(6) Capacitance unit conversion: 1F = 106μF = 1012PF; -
(7) electron volts (eV) is the unit of energy, 1eV = 1.60 × 10-19J; -
XI, constant current -
1. current intensity: I = q / t {I: current intensity (A), q: t at the time contained within a horizontal plane through the conductor of electricity (C), t: time (s)} -
2. Ohm's Law: I = U / R {I: conductor current intensity (A), U: voltage across the conductor (V), R: conductor resistance (Ω)} -
3. Resistance, Resistance Law: R = ρL / S {ρ: resistivity (Ω? m), L: length of conductor (m), S: conductor cross-sectional area (m2)} -
4. closed electric Lu Oumu Law: I = E / (r + R) or E = Ir + IR can also be E = U + U within the outside -
{I: total current in the circuit (A), E: electromotive force (V), R: the external circuit resistance (Ω), r: source resistance (Ω)} -
5. electric power and electrical power: W = UIt, P = UI {W: electric power (J), U: voltage (V), I: current (A), t: time (s), P: electrical power (W)} -
6. Joule's law: Q = I2Rt {Q: electric (J), I: current through the conductor (A), R: conductor resistance (Ω), t: power-on time (s)} -
7. pure resistance circuit: Since I = U / R, W = Q, so W = Q = UIt = I2Rt = U2t / R -
8. the power of total fixed rate, power output, power efficiency: P total = IE, P out = IU, η = P out / P Total {I: circuit total current (A), E: electromotive force (V ), U: Road-side voltage (V), η: power efficiency} -
9. Circuit series / parallel series circuit (P, U and R is proportional to) parallel circuit (P, I and R is inversely proportional to) -
electrical resistance (in collusion with and against) R series = R1 + R2 + R3 + 1 / R and = 1/R1 +1 / R2 +1 / R3 + -
current relationship I always = I1 = I2 = I3 I and = I1 + I2 + I3 + -
The total voltage relationship
U = U1 + U2 + U3 + U total = U1 = U2 = U3 -
power allocation P
total = P1 + P2 + P3 + P total = P1 + P2 + P3 + -
10. ohmmeter resistance measurement -
(1) circuit (2) measuring principle -
two tables document shorted, adjust the meter pointer over partial Ro may -
Ig = E / (r + Rg + Ro) -
After the measured resistance Rx
access the current through the meter -
Ix = E / (r + Rg + Ro + Rx) = E / (R in + Rx) -
corresponding to the Ix and Rx, it can indicate the size of the measured resistance -
(3) use: mechanical zero, select the range, zero ohms, measurement readings {Note gear (ratio)}, call off block. -
(4) Note: The measurement of resistance, to break the original circuit, select the range of the pointer near the center of each shift to re-zero ohm short circuit. -
11. TESTING RESISTANCE -
ammeter in connection: -
voltage indicates the number of: U = UR + UA -
external ammeter method: -
said current number: I = IR + IV -
Rx measurements = U / I = (UA + UR) / IR = RA + Rx> R true -
Rx measurements = U / I = UR / (IR + IV) = RVRx / (RV + R) > RA [or Rx> (RARV) 1 / 2] -
selected circuit conditions Rx Rx -
voltage regulation range, circuit complexity, power dissipation -
easy to adjust the voltage of the selection criteria Rp <Rx -
Note 1) unit conversion: 1A = 103mA = 106μA; 1kV = 103V = 106mA; 1MΩ = 103kΩ = 106Ω -
(2) the resistivity of various materials are changes with temperature, the metal resistivity with increasing temperature; -
(3) the total series resistance is greater than any sub-resistance, parallel resistance is less than any of the points of total resistance; -
(4) When the power supply internal resistance, the external circuit resistance increases, the total current decreases, the road-side voltage increases; -
(5) When the external circuit resistance is equal to the power resistor, power supply maximum output power, when the output power E2 / (2r); -
second, the magnetic field -
1. magnetic induction intensity is used to indicate the direction of the magnetic field strength and physical, is a vector, unit T), 1T = 1N / A? m -
2. Ampere force F = BIL; (Note: L ⊥ B) {B: magnetic flux density (T), F: Ampere force (F), I: current intensity (A), L: Cable length (m) } -
3. Lorentz force f = qVB (Note V ⊥ B); {f: Lorentz force (N), q: charged particle charge (C), V: Charged particle velocity (m / s)} -
4. the gravity is negligible (without regard to gravity) case, the movement of charged particles into the magnetic field conditions (bilingual): -
(1) charged particles into the magnetic field along the direction parallel to the magnetic field: the role of Lorentz force is not doing CV V = V0 -
(2) charged particles into the magnetic field along the direction perpendicular to the magnetic field: do uniform circular motion, the following rules a) F = f to Los = mV2 / r = mω2r = mr (2π / T) 2 = qVB; r = mV / qB; T = 2πm/qB; (b) exercise period and the radius of circular motion and the line speed has nothing to do, no Lorentz force acting on charged particles (all cases); (c) the key to solving problems: drawing trajectory, find the center , fixed radius, central angle (= double Xianqie Jiao). -
Note: -
(1) Ampere force and the Lorentz force direction can be determined by the left hand, but Lorentz force should pay attention to positive and negative charged particles; -
XIII, electromagnetic induction -
1) E = nΔΦ / Δt (universal formula) {Faraday's law of electromagnetic induction, E: induced voltage (V), n: induction coil turns, ΔΦ / Δt: the rate of change of magnetic flux} -
2) E = BLV vertical (cutting magnetic induction line movement) {L: effective length (m)} -
3) Em = nBSω (the largest alternator EMF) {Em: peak electromotive} -
4) E = BL2ω / 2 (ω conductor one end fixed to rotary cutting) {ω: angular velocity (rad / s), V: velocity (m / s)} -
2. flux Φ = BS {Φ: magnetic flux (Wb), B: uniform magnetic field of magnetic flux density (T), S: is on the area (m2)} -
3. electromotive force of the positive and negative direction of induced current can be used to determine the direction of current within the {power: the flow from the negative cathode} -
fourth, alternating current (sinusoidal alternating current) -
1. voltage instantaneous value e = Emsinωt current instantaneous value i = Imsinωt; (ω = 2πf) -
2. emf peak Em = nBSω = 2BLv current peak (pure resistance circuit) Im = Em / R General -
3. are (I) chord alternating current RMS: E = Em / (2) 1 / 2; U = Um / (2) 1 / 2; I = Im / (2) 1 / 2 - ;
4. ideal transformer coil in the former deputy voltage and current, and power relations -
U1/U2 = n1/n2; I1/I2 = n2/n2; P entry = P out -
5. In the long-distance transmission, the use of high-voltage transmission power can reduce power losses in transmission line loss '= (P / U) 2R; (P loss': the loss of power transmission lines, P: power transmission the total power, U: transport voltage, R: Transmission Line Resistance) -
6. formula 1,2,3,4 in the physical quantities and units: ω: angular frequency (rad / s); t: Time (s); n: number of turns; B: magnetic induction (T); -
S: coil area (m2); U Output) Voltage (V); I: current intensity (A); P: Power (W). -
Note: -
(1) changes in the frequency of alternating current in the coil and generator rotation is the same frequency: ω = ω line power, f = f power line; -
(2) generator, the coil magnetic flux in the neutral position of the largest surface, the induced emf is zero, the direction of current through the neutral plane to change; -
(3) valid values are defined according to the current heating effect, no particular means that the exchange value of all valid values; -
(4) ideal transformer turns ratio is constant, the output voltage is determined by the input voltage, input current is determined by the output current, input power is equal to output power, the power consumption when the load increases the input power also increases, P into the P out of the decision; -
fifth, electromagnetic oscillations and waves -
1.LC oscillator T = 2π (LC) 1 / 2; f = 1 / T {f: Frequency (Hz), T: Period (s), L: inductance (H), C: capacitance (F)} -
2. electromagnetic wave propagation speed in vacuum c = 3.00 × 108m / s, λ = c / f {λ: the wavelength of electromagnetic waves (m), f: wave frequency} -
Note: -
(1) process in the LC oscillator, the maximum charge the capacitor, the oscillating current is zero; the capacitor charge is zero, oscillating current maximum; -
(2) Maxwell's electromagnetic theory: changes in the electric (magnetic) field generated by the magnetic (electric) field; -
sixteen, light reflection and refraction (geometric optics) -
1. law of reflection α = i {α; reflection angle, i: angle} -
2. absolute refractive index (light from the vacuum to the media) n = c / v = sin / sin {dispersion of light, visible light in the refractive index of small red, n: refractive index, c: the speed of light in vacuum, v: the speed of light, medium,: angle,: angle of refraction} -
3. ATR: 1) light from the medium into the vacuum or air, total reflection occurs when the critical angle C: sinC = 1 / n -
2) total reflection conditions: light launched into optical sparse medium dense medium; angle of incidence is equal to or greater than the critical angle -
Note: -
(1) law of plane mirror reflection imaging: into the other large upright virtual image, such as mirror symmetry along with the object; -
(2) prism refracted image of the law: into the virtual image, a shot to the bottom edge of the deflection of light, such as the location of the vertex shift; -
seventh, the nature of light (light of both particles, but also volatility, known as wave-particle duality of light) -
1. two theories: that particles (Newton), the wave theory (Huygens) -
2. Double-slit interference: the middle of the light stripe; light stripe location: = nλ; dark stripes Location: = (2n +1) λ / 2 (n = 0,1,2,3 ,,,,); stripes {pitch: distance difference (OPD); λ: wavelength of light; λ / 2: half the wavelength of light; d the distance between the two slits; l: the distance between the bezel and screen} -
3. the color of light determined by the frequency of light, the light from the light source determine the frequency, and the media has nothing to do with the medium velocity of light is related to the color of light frequency from low to high by the order are: red, orange , yellow, green, blue, indigo, violet (mnemonic: the frequency of large violet wavelength small) -
4. thin film interference: thickness of antireflection coatings in the wavelength of green light in the film 1 / 4, the AR coating thickness d = λ / 4 P25〕 〔see Volume III -
5. light diffraction: Light in the absence of obstacles in the homogeneous medium is spread along a straight line, the size of the obstacle is much greater than the wavelength of light the case of diffraction of light along a straight line can be considered obvious transmission, otherwise, it can not be considered light travels in straight lines -
6. the light polarization: polarization of light that light wave -
7. electromagnetic light, said: Light is the essence of an electromagnetic wave. Electromagnetic spectrum (at wavelengths descending order): radio waves, infrared, visible light, ultraviolet, x rays, γ rays. IR, UV, line the discovery of roentgen rays and characteristics of the mechanism, the practical application -
8. photonic that a photon of energy E = hν {h: Planck's constant = 6.63 × 10-34J.s, ν: frequency of light} -
9. Einstein's photoelectric effect equation: mVm2 / 2 = hν-W {mVm2 / 2: initial photoelectron kinetic energy, hν: photon energy, W: work function metal} -
Note: -
(1) to distinguish the light will produce interference and diffraction theory, condition, design and applications, such as the double slit interference, thin film interference, diffraction, circular aperture diffraction, circular screen diffraction; -
(2) other related elements: the history of the Nature of Light Theory / Poisson bright spot / Emission / absorption spectrum / spectrum / spectrum of atom〕 〔see Volume III of the P50 / law of the photoelectric effect of photons that 〔 See Volume III P41〕 / optical tube and its application / wave-particle duality of light 〔〕 see Volume III of the P45 / P35 Laser〕 〔see Volume III / Volume III of the matter wave, see P51 〔〕. -
-
eighth, atoms and nuclei -
1.α scattering results a) most of the α-particle is not deflected; (b) place a small number of α particles larger deflection angle; (c) very small number of big α-particle deflection angle (or even rebound back) -
2. nucleus size :10-15 ~ 10-14m, the atomic radius of about 10-10m (the atomic nucleus structure) -
3. Photon emission and absorption: atomic transition occurs when the steady state, to radiation (or absorption) of a certain frequency of the photon: hν = E {end early-E level transition} -
4. the composition of the nucleus: protons and neutrons (collectively known as nucleons), {A = mass number = protons + neutrons, Z = charge number = protons = atomic number = number of extranuclear 〔see three P63〕} -
5. Natural radioactivity: α radiation (α particles are helium nuclei), β-ray (high-speed movement of the electron flow), γ-ray (very short wavelength electromagnetic waves), α decay and β decay, half-life (more than half The nuclei of the decay with time). γ-ray is accompanied by the α and β-ray radiation produced by P64〕 〔see Volume III -
6. Einstein's mass-energy equation: E = mc2 {E: energy (J), m: mass (Kg), c: the speed of light in vacuum} -
7. nuclear energy calculated ΔE = Δmc2 {if Δm kg when using the unit, ΔE units of J; when Δm with the atomic mass unit u, the calculated ΔE units uc2; 1uc2 = 931.5MeV} 〔see three P72〕. -
Note: -
(1) the common nuclear reaction equation (heavy nuclear fission, nuclear fusion and other nuclear reaction equation of light) required to master; -
(2) Learn the common mass of the particle number and mass number; -
(3) the number of conservation of mass and charge, based on experimental facts, is the right equation to write the key nuclear reactions; -
(4) other related elements: hydrogen atom structure of P49〕 〔see Volume III / hydrogen atom the electron cloud of P53〕 〔see Volume III / and application of radioactive isotopes, radioactive pollution and the protection 〔see Volume III P69〕 / heavy nuclear fission, chain reaction, chain reaction conditions, see Volume III P73 nuclear reactor 〔〕 / light fusion, controlled thermonuclear reaction, see Volume III P77 〔〕 / physical structure of the human understanding. (End) -
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left hand rule: -
left hand rule (Ampere is set): Given the current direction and the direction of the magnetic induction lines, power conductor in a magnetic field to determine the force direction, such as electric motors. -
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outstretched left hand, the magnetic induction line penetration palm (palm of the hand aligned N pole, S pole aligned back of the hand), four fingers point to the current direction, then the direction of thumb is to force the direction of the conductor. -
The principle is: -
magnet when you sense the magnetic flux lines and current lines are being drawn when the two magnetic induction lines are intertwined, according to vector addition, the magnet and the current direction of the magnetic induction lines the same place, magnetic induction line becomes dense; in the opposite direction where the magnetic induction lines become sparse. Magnetic induction lines are a feature that is, each line of a magnetic sense of mutually exclusive! Intensive local magnetic induction line So the pressure on both sides of the different currents, the current pressure to one side. The direction of the thumb is the direction of this pressure. -
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right-hand rule: -
determine the conductor cutting magnetic induction line movement in the conductor direction of the induced current rule. (Generator) -
right-hand rule reads: outstretched right hand, the thumb with the other four fingers, and are related to hand in a vertical plane, the right hand placed in a magnetic field, so that the vertical penetration of the magnetic induction lines palm, thumb point to the direction of conductor movement, the remaining four fingers pointing to the direction of induced current.
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Linear Mode
