There are two resistors to connect them in series. The total resistance is 10 ohm and the parallel resistance is 2.1 ohm. What are the resistance values of these two resistors?

There are two resistors to connect them in series. The total resistance is 10 ohm and the parallel resistance is 2.1 ohm. What are the resistance values of these two resistors?

Let one be x ohm and the other be y ohm
x+y=10
（x*y）/(x+y)=2.1
The results of solving equations
x=3
y=7

4. What are the characteristics of multiples 6, 7, 8, 9, 11 and 13? Please give an example to show how to judge whether a number is a multiple of 4, 6, 7, 8, 9, 11 and 13?

If the sum of each digit is a multiple of 9, then the number is a multiple of 9
If the bits of a number are 0 or 5, then the number is a multiple of 5
If a number is an even number and the sum of each digit is a multiple of 3, the number is a multiple of 6

Is it current or voltage that affects the brightness of the bulb?

Light bulb is the filament because of high temperature and glow, filament glow by the size of the current through the decision, and in the case of constant filament, the greater the voltage, the greater the current flow, the more intense the glow

9x & # 178; - Y & # 178; = 48 x + y = 6 find the value of X, y

Method 1: it can be regarded as a system of equations and solved
Method 2: it can be seen as the intersection of hyperbola 9x & # 178; - Y & # 178; = 6 and straight line 48x + y = 6, draw the image, and find the intersection coordinates

As shown in the figure, the range of the ammeter is 0-0.6, the range of the voltmeter is 0-15 Ω, the resistance R = 30 Ω, and the voltage at both ends of the circuit is 24 v
When the resistance of the sliding rheostat connected into the circuit is too small, the current in the circuit will exceed the range of the ammeter

1. Voltage of R0 measured by Voltmeter: in series circuit, the current passing through R0 resistor should be loop current. Limited by the range of voltmeter, the maximum voltage at both ends of R0 is 15V. Then: I = u resistance / R0 = 15 / 30 = 0.5A; (within the range of ammeter). The voltage added to RW is & nbsp; u variable = u total - U resistance = 24-15 = 9 (V) & nbsp; R variable = u variable / I = 9 / 0.5 = 18 (Ohm), The r-transformer should be greater than or equal to 18 ohm. 2. The voltage of measuring RW by Voltmeter: the range of ammeter is the maximum return current, which is 0.6A. R total = u total / I = 24 / 0.6 = 40 (Ohm) & nbsp; R variable = R total - R0 = 40-30 = 10 (Ohm). The voltage of r-transformer is measured by Voltmeter & nbsp; u variable = IR variable = 0.6 * 10 = 6 (V) & nbsp; (within the range of voltmeter). When the ammeter is the maximum measured value (15V), the voltage of r-transformer is measured by voltmeter, RW is the maximum adjustable value of rheostat. The voltage applied to R0 is 9V. The loop current I = u resistance / R0 = 9 / 30 = 0.3 (a) & nbsp; R variable = u variable / I = 15 / 0.3 = 50 (Ohm). Therefore, the adjustable resistance range of rheostat is 10 to 50 ohm

Given the equation AX = B, when a is not equal to 0, the equation has a solution. This solution is () when a = 0, B = 0, the equation has a solution when a = 0, B is not equal to 0

(1) When the equation can be changed to: a (x-0) (x-0) = 0, two of them are 0, then B = C = 0 (2) because there is a root of 0, so x = 0 is substituted, so C = 0, then the equation can be changed to: ax (x + BX / a) = 0, when B ≠ 0, the other root - B / A is not 0, so B ≠ 0, C = 0 (3) X1 + x2 = 0-B / a = 0 (Veda theorem) B = 0 (4) because there is

What is the volume resistivity of silicone rubber

The volume resistivity at 20 ℃ ranges from the 9th power of 10 to the 15th power of 10 Ω * M

Judge the parity of the following functions f (x) = (√ 1-x & # 178;) / (| x + 2 | - 2)

The root sign is 1-x & # 178; > = 0
-1

Please list the rated power of common household appliances

Air conditioner 1000W
Microwave oven 1000W
Electric furnace 1000W
Electric water heater 1000W
Vacuum cleaner 800W
Hair dryer 500W
Electric iron 500W
Washing machine 500W
TV 200W
Computer 200W
Range hood 140W
Refrigerator 100W
Electric fan 100W
Flashlight 0.5W
Calculator 0.5MW
Electronic meter 0.01mw

19.8 + 29.7 + 39.6 + 49.5 =? 8.9 + 9.4 + 9.2 + 9.5 + 9.3 + 8.8 =? Simple calculation
Ningxia putianxia Zhengyuan School District Fifth Grade excellent training class mathematics volume 3 page 26 strengthen improve 1 question, 2 questions and 4 questions

19.8+29.7+39.6+49.5=(20－0·2)＋(30－0·3)＋(40－0·4)＋(50－0·5)=(20＋30＋40＋50)－(0·2＋0·3＋0·4＋0·5)=140－1·4=138·68.9+9.4+9.2+9.5+9.3+8.8=(9－0·1)＋(9＋0·4)＋（9＋0·2）＋（9＋0·5）＋（...