Summary of Physics Knowledge Points in Senior Two

Mastering each knowledge point will enable you to

examination

Physical knowledge points of senior two in the first semester: electrostatic field

1. Two kinds of charges, charge conservation law, elementary charge: (e=1.60 × 10-19c); The amount of charged body charge is equal to the integral multiple of elementary charge.

2. Coulomb's law: f=kq1q2/r2 (in vacuum) {f: force between point charges (n), k: electrostatic constant k=9.0 × 109n? M2/c2, q1, q2: electric quantity of two-point charges (c), r: distance between two-point charges (m), direction is on their line, force and reaction force, same kind of charges repel each other, and different kinds of charges attract each other

3. Electric field intensity: e=f/q (definition formula, calculation formula) {e: electric field intensity (n/c), which is a vector (superposition principle of electric field), q: electric quantity of checking charge (c)

4. Electric field formed by vacuum point (source) charge e=kq/r2 {r: distance from source charge to this position (m), q: electric quantity of source charge}

5. Field strength of uniform electric field e=uab/d {uab: voltage between ab two points (v), d: distance between ab two points in the direction of field strength (m)}

6. Electric field force: f=qe {f: electric field force (n), q: electric quantity of charge subject to electric field force (c), e: electric field strength (n/c)

7. Potential and potential difference: uab=φ a - φ b, uab=wab/q=- δ eab/q

8. Work done by electric field force: wab=quab=eqd {wab: work done by electric field force when the charged body moves from a to b (j), q: charge (c), uab: potential difference between two points a and b in the electric field (v) (work done by electric field force is independent of the path), e: uniform electric field strength, d: distance between two points along the direction of field strength (m)

9. Electric potential energy: ea=q φ a {ea: electric potential energy of charged body at point a (j), q: electric quantity (c), φ a: electric potential at point a (v)

10. Change of electric potential energy δ eab=eb ea {Difference of electric potential energy of charged body from position a to position b in electric field

11. Work done by electric force and change of electric potential energy δ eab=- wab=- quab (the increment of electric potential energy is equal to the negative value of work done by electric force)

12. Capacitance c=q/u (definition formula, calculation formula) {c: capacitance (f), q: electric quantity (c), u: voltage (potential difference between two plates) (v)

13. The capacitance of the parallel plate capacitor c=ε s/4 π kd (s: the area directly opposite the two plates, d: the vertical distance between the two plates, ω: the dielectric constant)

14. Acceleration of charged particles in electric field (vo=0): w=δ ek or qu=mvt2/2, vt=(2qu/m) 1/2

15. Deflection of charged particles entering the uniform electric field with velocity vo along the vertical electric field direction (without considering the gravity effect)

Quasi horizontal vertical electric field direction: uniform linear motion l=vot (in parallel polar plates with equal heterogeneous charges: e=u/d)

The throwing motion is parallel to the electric field direction: the uniformly accelerated linear motion with zero initial velocity d=at2/2, a=f/m=qe/m

Note:

(1) When two identical charged metal balls contact, the electricity distribution law: the original heterogeneous charge is neutralized first and then shared equally, and the total amount of the original homogeneous charge is shared equally;

(2) The electric field line starts from the positive charge and ends at the negative charge. The electric field line does not intersect. The tangent direction is the direction of field strength. The field is strong where the electric field line is dense. The electric potential along the electric field line is getting lower and lower, and the electric field line is perpendicular to the equipotential line;

(3) The electric field line distribution requirements of common electric fields shall be memorized [see Figure [Volume II p98];

(4) The electric field strength (vector) and potential (scalar) are determined by the electric field itself, and the electric field force and potential energy are also related to the quantity of electricity and the positive and negative charges of the charged body;

(5) The conductor in electrostatic balance is an equipotential body, the surface is an equipotential surface, the electric field line near the outer surface of the conductor is perpendicular to the surface of the conductor, the combined field strength inside the conductor is zero, there is no net charge inside the conductor, and the net charge is only distributed on the outer surface of the conductor;

(6) Capacitance unit conversion: 1f=106 μ f=1012pf;

(7) Electron voltage (ev) is the unit of energy, 1ev=1.60 × 10-19j;

(8) Other relevant contents: electrostatic shielding [see p101 in Volume II]/oscilloscope, oscilloscope and their applications [see p114 in Volume II] equipotential surface [see p105 in Volume II].

Physics knowledge in the first semester of senior two: constant current

1. Current intensity: i=q/t {i: current intensity (a), q: electric quantity passing through conductor transverse load surface in time t (c), t: time (s)

2. Ohm's law: i=u/r {i: conductor current intensity (a), u: voltage at both ends of conductor (v), r: conductor resistance (ω)

3. Resistance, resistance law: r=ρ l/s {ρ: resistivity (ω? M), l: conductor length (m), s: conductor cross-sectional area (m2)

4. Ohm's law of closed circuit: i=e/(r+r) or e=ir+ir can also be e=u inside+u outside

{i: total current in the circuit (a), e: power supply electromotive force (v), r: external circuit resistance (ω), r: power supply internal resistance (ω)

5. Electric work and power: w=uit, p=ui {w: electric work (j), u: voltage (v), i: current (a), t: time (s), p: electric power (w)}

6. Joule's law: q=i2rt {q: electric heating (j), i: current passing through conductor (a), r: resistance of conductor (ω), t: power on time (s)

7. In the pure resistance circuit: because i=u/r, w=q, and three factors, w=q=uit=i2rt=u2t/r

8. Total power rate, power output power, power efficiency: pTotal=ie, pOutput=iu, η=pOutput/pTotal {i: total circuit current (a), e: power electromotive force (v), u: terminal voltage (v), η: power efficiency

9. Series/parallel series circuit of circuit (p, u are proportional to r) Parallel circuit (p, i are inversely proportional to r)

Resistance relation (series same parallel reverse) r series=r1+r2+r3+1/r parallel=1/r1+1/r2+1/r3+

Current relation i total=i1=i2=i3i and=i1+i2+i3+

Voltage relation uTotal=u1+u2+u3+uTotal=u1=u2=u3

Power distribution pTotal=p1+p2+p3+pTotal=p1+p2+p3+

Physics knowledge in the first semester of senior two: magnetic field

1. Magnetic induction intensity is a physical quantity used to indicate the strength and direction of the magnetic field. It is a vector, unit: t), 1t=1n/a? m

2. Ampere force f=bil; (Note: l ∨ b) {b: magnetic induction (t), f: ampere force (f), i: current intensity (a), l: conductor length (m)}

3. Lorentz force f=qvb (note v ∨ b); Mass spectrometer [see p155 in Volume II] {f: Lorentz force (n), q: charged particle electricity (c), v: charged particle velocity (m/s)}

4. When gravity is ignored (gravity is not considered), the movement of charged particles into the magnetic field (master two types):

(1) Charged particles enter the magnetic field along the direction parallel to the magnetic field: they are not affected by Lorentz force and move in a uniform straight line v=v0

(2) Charged particles enter the magnetic field along the direction perpendicular to the magnetic field: they move in a uniform circular motion with the following laws: a) direction f=fLo=mv2/r=m ω 2r=mr (2 π/t) 2=qvb; r=mv/qb;t=2πm/qb; (b) The period of motion is independent of the radius and linear velocity of circular motion, and the Lorentz force does no work on charged particles (under any circumstances); (c) Key to solving the problem: draw the track, find the center of the circle, fix the radius and the center angle (=twice the chord tangent angle).

Note:

(1) The direction of ampere force and Lorentz force can be determined by the left hand rule, but Lorentz force should pay attention to the positive and negative of charged particles;

(2) The characteristics of magnetic induction lines and the distribution of magnetic induction lines of common magnetic fields should be mastered [see figure and p144 in Volume II]; (3) Other relevant contents: geomagnetic field/principle of magnetoelectric meter [see p150 in Volume II]/cyclotron [see p156 in Volume II]/magnetic materials

=103mh=106μh。 (4) Other relevant contents: Self induction [see p178 in Volume II]/fluorescent lamp [see p180 in Volume II].

Physics knowledge point of senior two science: electric field

1. Coulomb's law: f=kq1q2/r2 (in vacuum) {f: force between point charges (n), k: electrostatic constant k=9.0 × 109n? M2/c2, q1, q2: electric quantity of two-point charges (c), r: distance between two-point charges (m), direction is on their line, force and reaction force, same kind of charges repel each other, and different kinds of charges attract each other

2. Two kinds of charges, charge conservation law, elementary charge: (e=1.60 × 10-19c); The charge amount of charged body is equal to the integral multiple of elementary charge

3. Electric field intensity: e=f/q (definition formula, calculation formula) {e: electric field intensity (n/c), which is a vector (superposition principle of electric field), q: electric quantity of checking charge (c)

4. The electric field formed by the vacuum point (source) charge e=kq/r2 {r: distance from the source charge to the position (m), q: electric quantity of the source charge}

5. Electric field force: f=qe {f: electric field force (n), q: electric quantity of charge subject to electric field force (c), e: electric field strength (n/c)

6. Field strength of uniform electric field e=uab/d {uab: voltage between ab two points (v), d: distance between ab two points in the direction of field strength (m)}

7. Potential and potential difference: uab=φ a - φ b, uab=wab/q=- δ eab/q

8. Work done by electric field force: wab=quab=eqd {wab: work done by electric field force when the charged body moves from a to b (j), q: charge (c), uab: potential difference between two points a and b in the electric field (v) (work done by electric field force is independent of the path), e: uniform electric field strength, d: distance between two points along the direction of field strength (m)

9. Electric field force work and electric potential energy change δ eab=- wab=- quab (the increment of electric potential energy is equal to the negative value of electric field force work)

10. Electric potential energy: ea=q φ a {ea: electric potential energy of charged body at point a (j), q: electric quantity (c), φ a: electric potential at point a (v)

11. Change of electric potential energy δ eab=eb ea {Difference of electric potential energy of charged body from position a to position b in electric field}

12. Capacitance c=q/u (definition formula, calculation formula) {c: capacitance (f), q: electric quantity (c), u: voltage (potential difference between two plates) (v)

13. The capacitance of the parallel plate capacitor c=ε s/4 π kd (s: the area directly opposite the two plates, d: the vertical distance between the two plates, ω: the dielectric constant)

14. Acceleration of charged particles in electric field (vo=0): w=δ ek or qu=mvt2/2, vt=(2qu/m) 1/2

15. Deflection of charged particles entering the uniform electric field with velocity vo along the vertical electric field direction (without considering the gravity effect)

Quasi horizontal vertical electric field direction: uniform linear motion l=vot (in parallel polar plates with equal heterogeneous charges: e=u/d)

The throwing motion is parallel to the electric field direction: the uniformly accelerated linear motion with zero initial velocity d=at2/2, a=f/m=qe/m

[Physics knowledge points in senior two

summary