How does the circuit in Kirchhoff's law count branches?

How does the circuit in Kirchhoff's law count branches?

No bifurcation is a branch, three (including) more than the intersection of the branch is the node. Calculate. The first floor only gives a general analysis, node is three branches connected together called node. Is a branch!

Kirchhoff's law,
E1 = E2 = 17V, R1 = 10 Ω, R2 = 5 Ω, R3 = 2 Ω, calculate ABC three-point current

The correlation equation is as follows
E1－i1R1＝E2＋i2R2
E2＋i2R2＝i3R3
i1＝i2＋i3
The results show that I1 = 1.0625a, I2 = - 2.125a, I3 = 3.1875a

Does changing the reference direction of current or voltage affect the verification of Kirchhoff's law? Why?

The fundamental principle of Kirchhoff's voltage law is that the sum of loop voltages is zero. The fundamental principle of Kirchhoff's current law is that the loop currents are equal. Therefore, changing the voltage or current direction will not affect the fundamental law that the sum of voltages is zero and the loop currents are equal. Therefore, it has no influence on the verification of Kirchhoff's law

Please use the quadratic equation to solve!
1. Uncle Wang contracted 25 cubic meters of land. This spring, he planted two kinds of greenhouse vegetables, eggplant and tomato, which cost 44000 yuan. Among them, 1700 yuan was used for eggplant per cubic meter and the net profit was 2400 yuan; 1800 yuan was used for tomato per cubic meter and the net profit was 2600 yuan. How many yuan was Uncle Wang's total net profit?
2. The following table shows the daily closing prices of a and B stocks in a certain week
Monday, Tuesday, three, four, five
A 12.5 12.9 12.45 12.75
B 13.5 13.3 13.9 13.4 13.15
If a person holds a number of shares of a and B in that week, according to the daily closing price of the two shares (excluding handling fees and taxes), the person's account made 200 yuan more profit last Tuesday than on Monday, and 1300 yuan more profit on Wednesday than on Tuesday?

1: According to the meaning of the title, set X cubic meters of Eggplant and Y cubic meters of tomato. Then Uncle Wang's profit is Z = 2400x + 2600y. According to the meaning of the title, we can get x = 10 and y = 15 from the above two formulas. Therefore, Uncle Wang's profit is z = 2400 * 10 + 2600 * 15 = 6300

Known sequence an = 3,10,21,36 Formula for finding general term

an=3,10,21,36……
3=1×3
10=2×5
21=3×7
36=4×9
.
an=n×(n+n+1)=n×(2n+1)

The diameter of a hair

80 micron

Mathematical problems (solving linear equations with one variable)
1. When m = (), the solutions of equation 5x + 4 = 4x-3 and equation 2 (x + 1) - M = - 2 (m-2) are the same
2. When y = (), the values of Y-8 / 3 and 1 / 2-8-y / 6 are equal
3. Solve the following equation
（1）5（x-5）+2x＝-4
（2）5（2x+1）-3（22x+11）＝4（6x+3）
（3）2x+1 /4 -1 ＝ x- 10x+1 /12
4. Affected by the weather and other factors, the prices of some agricultural products have risen this year. Uncle Zhang has made a total profit of 13800 yuan from the two kinds of vegetables planted in the contracted 10 mu land, of which 1200 yuan per mu is for type a vegetables and 1500 yuan per mu is for type B vegetables. How many Mu are Uncle Zhang planting for type A and type B vegetables?

1. When m = - 16, the solutions of equation 5x + 4 = 4x-3 and equation 2 (x + 1) - M = - 2 (m-2) are the same. 2. When y = - 29 / 7, the values of Y-8 / 3 and 1 / 2-8-y / 6 are equal. 3. Solve the following equation (1) x = 3 (2) x = - 1 / 2 (3) x = 5 / 66 (4)

What's the next digit?

6

2 + 2 / 3 = 2 square * 2 / 3, 3 + 3 / 8 = 3 square * 38, 4 + 4 / 15 = 4 square * 4 / 15, if 9 + B / a = 9 square * B / A, then a + B =?
There should be a formula,

Rule: n + n / (n & # 178; - 1) = n & # 178; × n / (n & # 178; - 1)
Then when n = 9, a = n & # 178; - 1 = 81-1 = 80, B = n = 9
So: a + B = 80 + 9 = 89

Summary of all the formulas in the second volume of physics of the people's Education Press

(1) series circuit P (electric power) U (voltage) I (current) w (electric work) r (resistance) t (time)
The current is equal everywhere, I1 = I2 = I
The total voltage is equal to the sum of the voltages at both ends of each consumer, u = U1 + U2
The total resistance is equal to the sum of the resistances r = R1 + R2
U1：U2=R1：R2
The total electric work is equal to the sum of the electric work w = W1 + W2
W1：W2=R1：R2=U1：U2
P1：P2=R1：R2=U1：U2
The total power is equal to the sum of the powers, P = P1 + P2
(2) parallel circuit
The total current is equal to the sum of the currents I = I1 + I2
The voltage is equal everywhere U1 = U1 = U
The total resistance is equal to the product of the resistances divided by the sum of the resistances r = r1r2 △ (R1 + R2)
The total electric work is equal to the sum of the electric work w = W1 + W2
I1：I2=R2：R1
W1：W2=I1：I2=R2：R1
P1：P2=R2：R1=I1：I2
The total power is equal to the sum of the powers, P = P1 + P2
(3) electric power of the same electrical appliance
① The ratio of rated power to actual power is equal to the square of rated voltage to actual voltage, PE / PS = (UE / US)
2. Formula of circuit
(1) resistance R
① Resistance is equal to the density of the material multiplied by (length divided by cross-sectional area) r = density × (L △ s)
② Resistance is equal to voltage divided by current R = u △ I
③ The resistance is equal to the square of the voltage divided by the electric power r = UU △ P
(2) electric power W
Electric work is equal to current times voltage times time w = uit (common formula)
Electric work is equal to electric power times time w = Pt
Electric work is equal to charge times voltage w = QT
Electric work is equal to the square of current times resistance times time w = I × IRT (pure resistance circuit)
Electric work is equal to the square of voltage divided by resistance and then multiplied by time w = u &; u △ R × t (same as above)
(3) electric power p
① Electric power is equal to voltage times current, P = UI
② Electric power is equal to the square of current multiplied by resistance P = IIR (pure resistance circuit)
③ The electric power is equal to the square of the voltage divided by the resistance P = UU △ R (as above)
④ Electric power is equal to electric work divided by time p = w: T
(4) electric heating Q
Electric heating is equal to the square of electric current, which is resistance times time q = iirt (common formula)
Electric heating is equal to current times voltage times time q = uit = w (pure resistance circuit)