All formulas for physics and electricity in the second year of junior high school, and formulas for

Series: i=i1+i2 u=u1=u2 r=r1+r2 parallel: i=i1=i2 u=u1+u2 r=r1xr2 r1+r2 Ohm's law formula:

The meaning and unit of the i=u r symbol:

U--- voltage --- volts (V).

r--- resistance --- ohms ( ).

I --- current ---ampere (a).

Electrical Power Formula:

The meaning and unit of the p=w t symbol:

w --- the electrical energy consumed --- joules (j).

The time taken by t--- --- seconds (s).

p--- electrical power --- watts (W).

1kw (kilowatt) = 1000w

Electrical power derivative:

p=w/t=uit/t=ui

p=ui=iri=i*ir (only for heat-generating circuits) p=ui=u*(u r)=u*u r

The meaning and unit of the symbol:

U--- voltage --- volts (V).

I --- current ---ampere (a).

w --- the electrical energy consumed --- joules (j).

The time taken by t--- --- seconds (s).

p--- electrical power --- watts (W).

I said it above).

Joule's law: q=i*irt (i*i denotes the power of i).

The meaning and unit of the symbol:

Q --- caloric --- joules (j).

I --- current ---ampere (a).

The time taken by t--- --- seconds (s).

r--- resistance --- ohms ( ).

Electromagnetic Wave Frequency:

c= f (read: lambut).

The meaning and unit of the symbol:

c--- The speed of the wave is not limited to --- unit (the speed of electromagnetic waves is the speed of light 3 * 10 to the eighth power of seconds) - the wavelength --- is unified with the speed of the wave.

f--- frequency--- hertz (Hz).

Current. The defining formula is i=q t

Ohm's law i = u r

Series circuit i=i1=i2

Parallel circuit i=i1+i2

Voltage. Series circuit u=u1+u2

Parallel circuit u=u1=u2

Resistance. Total series r = r1 + r2

Total parallel r = r1r2 (r1+r2).

i=u/ru=ir

r=u/ip=w/t

p=uip=u^/r

p=i^rq=uit

q=u^/rt

q=i^rt

Tandem: i total = i1 = i2 *****

u=u1+u2+++

p total = p1 = p2 +++

Total w = w1 + w2 + + +

u1/u2=r1/r2

r total = r1 + r 2 + + +

Parallel: i total = i1 + i2 + + +

u=u1=u2*****=

p total = p1 = p2 +++

1 r total = 1 r1 + 1 r2+++

Total w = w1 + w2 + + +

Ohm's law i = u r

Joule's law: q = i 2rt

Deformation formula: q=uit

q=u^/rt

ps：w=pt

The time taken by t--- --- seconds (s).

p--- electrical power --- watts (W).

1kw (kilowatt) = 1000w

Electrical power derivative:

p=w/t=uit/t=ui

p=ui=iri=i*ir (only for heat-generating circuits) p=ui=u*(u r)=u*u r

The meaning and unit of the symbol:

U--- voltage --- volts (V).

I --- current ---ampere (a).

w --- the electrical energy consumed --- joules (j).

The time taken by t--- --- seconds (s).

p--- electrical power --- watts (W).

I said it above).

Joule's law: q=i*irt (i*i denotes the power of i).

The meaning and unit of the symbol:

Q --- caloric --- joules (j).

I --- current ---ampere (a).

The time taken by t--- --- seconds (s).

r--- resistance --- ohms ( ).

Electromagnetic Wave Frequency:

c= f (read: lambut).

The meaning and unit of the symbol:

c--- The speed of the wave is not limited to --- unit (the speed of electromagnetic waves is the speed of light 3 * 10 to the eighth power of seconds) - the wavelength --- is unified with the speed of the wave.

f--- frequency--- hertz (Hz).

1. Ohm's Law Section.

1 i = u r (Ohm's law: the current in a conductor is proportional to the voltage across the conductor and inversely proportional to the resistance of the conductor).

2． i=i1=i2=…=in (characteristic of the current in a series circuit: the currents are equal everywhere).

3． u=u1+u2+…+un (characteristic of voltage in series circuits: in series circuits, the total voltage is equal to the sum of the voltages at both ends of each part of the circuit).

4． i=i1+i2+…+IN (characteristic of the current in a parallel circuit: the current on the main circuit is equal to the sum of the currents in each branch).

5． u=u1=u2=…=un (Characteristics of voltage in parallel circuits: The voltage at both ends of each branch is equal. are equal to the supply voltage).

6． r=r1+r2+…+rn (characteristic of resistance in series circuits: the total resistance is equal to the sum of the resistances of the parts of the circuit).

7． 1/r=1/r1+1/r2+…+1 rn (characteristic of resistors in parallel circuits: the reciprocal of the total resistors is equal to the sum of the reciprocals of the various parallel resistors).

8 r and = r n (the formula for finding the total resistance when n identical resistors are connected in parallel).

9 r string = nr (the formula for finding the total resistance when n of the same resistor in series).

10 u1:u2=r1:r2 (the relationship between voltage and resistance in a series circuit: the ratio of voltage is equal to the ratio of resistance to which they correspond).

11 i1:i2=r2:r1 (the relationship between current and resistance in parallel circuits: the ratio of current is equal to the inverse ratio of the resistance to which they correspond).

2. Electric power part.

12 p=ui (empirical, suitable for any circuit).

13 p=w t (defined, suitable for any circuit).

14 q=i2rt (Joule's law, suitable for any circuit).

15．p=p1+p2+…+PN (suitable for any circuit).

16 W=UIT (empirical, suitable for any circuit).

17.p=i2r (composite formula, only suitable for purely resistive circuits).

18.p=u2 r (composite formula, only suitable for purely resistive circuits).

19.w=q (empirical, only suitable for purely resistive circuits.) where w is the work done by the current flowing through the conductor and q is the heat produced by the current flowing through the conductor).

20.w=i2rt (composite formula, only suitable for purely resistive circuits).

21.w=u2t r (composite formula, suitable only for purely resistive circuits).

22 p1:p2=u1:u2=r1:r2 (the relationship between electrical power and voltage and resistance in a series circuit: in a series circuit, the ratio of electrical power is equal to the ratio of voltage and resistance corresponding to them).

23 p1:p2=i1:i2=r2:r1 (the relationship between electrical power and current and resistance in parallel circuits: in parallel circuits, the ratio of electrical power is equal to the ratio of the current corresponding to them and equal to the inverse ratio of their corresponding resistance).

The formula for physics and electricity in the third year of junior high school is as follows:1. Current intensity: i=q power t

2. Resistance: r= l s

3. Ohm's law: i=u r

4. Joule's Law:

1) Q=I2RT universal formula).

2) Q = UIT = PT = UQ power = U2T R (pure resistance formula) 5, series circuit:

1）i=i1=i2

2）u=u1+u2

3) R=R1+R2(1)W=UIT=PT=UQ (universal formula) (2) W=I2RT=U2T R (pure resistance formula) (4) U1 U2=R1 R2 (partial pressure formula).

5）p1/p2=r1/r2

6. Parallel circuit:

1）i=i1+i2

2）u=u1=u2

3) 1 r=1 r1+1 r2[r=r1r2 (r1+r2)](4)i1 i2=r2 r1 (shunt formula).

5）p1/p2=r2/r1

7. Fixed-value resistance:

1）i1/i2=u1/u2

2）p1/p2=i12/i22

3）p1/p2=u12/u22

8. Electric work: (1) w = uit = pt = uq (universal formula) (2) w = i2rt = u2t r (pure resistance formula) 9, electric power:

1) p=w t=ui (universal formula).

2) P=I2R=U2 R (pure resistance formula).

The formula for the third year of physics is as follows:1. Current intensity: i=q power t

2. Resistance: r= l s

3. Ohm's law: i=u r

4. Joule's Law:

1) Q=I2RT universal formula).

2) Q = UIT = PT = UQ Electricity = U2t R (pure resistance formula).

5. Series circuit:

1)i=i1=i2。

2)u=u1+u2。

3)r=r1+r2。

4) w=uit=pt=uq (universal formula).

5) W=I2RT=U2T R (pure resistance formula).

6) u1 u2=r1 r2 (partial pressure formula).

7)p1/p2=r1/r2。

6. Parallel circuit:

1)i=i1+i2。

2)u=u1=u2。

3)1/r=1/r1+1/r2[r=r1r2/(r1+r2)]。

4) i1 i2 = r2 r1 (shunt formula).

5)p1/p2=r2/r1。

7. Fixed-value resistance:

1)i1/i2=u1/u2。

2)p1/p2=i12/i22。

3)p1/p2=u12/u22。

8. Electric work: 1) w=uit=pt=uq (universal formula).

2) w=i2rt=u2t r (pure resistance formula).

9. Electric power:

1) p=w t=ui (universal formula).

2) P=I2R=U2 R (pure resistance formula).

The formula for electricity in the third year of physics is as follows:

1. Explanation of physical and electrical formulas.

1. For the three physical quantities of electric work, electric power, and electric heat, whether they are in series or parallel circuits, the total amount is equal to the sum of all parts.

2. Use Ohm's law i=u r to find the current in the circuit, so that students can understand that this formula is derived from experiments and is the most basic formula in electricity, but this formula is only suitable for pure resistive circuits.

3. The two formulas of electric power solution P=W t and P=UI are the two most basic formulas commonly used in the calculation of electric power in electricity, the first is the definition of electric power, and it is also often used as a formula for measuring the electric power of household appliances with energy meters and clocks.

4. There are only 4 basic formulas of electricity, namely: i=u r, p=w t, p=ui, q=i2rt.

5. Several important derivation formulas should be proficient.

Second, the specific formula.

1、i=p/u。

2、u=ir。

3、r=u/i。

4、r=u2/p。

5、p=u2/r。

6、p=i2r。

7、p=w/t。

8、q=i2rt。

3. Expand the mechanics part of the formula.

1. Speed formula.

The distance that the train passes when crossing the bridge (hole) s l bridge l car.

The speed of sound propagation in the air is 340m s.

The speed of light propagation in the air is 3 108m s.

2. Density formula.

Water. When there is a change in the state between ice and water, m water, m ice.

water ice; v water v ice.

The volume of the hollow part of the hollow sphere v the total v solid.

A complete list of common formulas in junior high school physics: electricity. 1. Current intensity: i=q power t

2. Resistance: r= l s

3. Ohm's law: i=u r

4. Joule's Law:

1) Q=I2RT universal formula).

2) Q = UIT = PT = UQ Electricity = U2t R (pure resistance formula).

5. Series circuit:

1)、i=i1=i2。

2)、u=u1+u2。

3), r=r1+r2(1), w=uit=pt=uq (universal formula). 2) w=i2rt=u2t r (pure resistance formula).

4), u1 u2=r1 r2 (partial pressure formula).

5)、p1/p2=r1/r2。

6. Parallel circuit:

1)、i=i1+i2。

2)、u=u1=u2。

r=1/r1+1/r2[r=r1r2/(r1+r2)]。

4) i1 i2 = r2 r1 (shunt formula).

5)、p1/p2=r2/r1。

7. Fixed-value resistance:

1)、i1/i2=u1/u2。

2)、p1/p2=i12/i22。

3)、p1/p2=u12/u22。

8. Electric work: 1) w=uit=pt=uq (universal formula).

2) w=i2rt=u2t r (pure resistance formula).