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Calculation of "Ohm's law" and "electric power" in Physics It must be a calculation. Don't fill in the blanks It's better to have short questions, the more the better
1. (2006 &; Sanming City) as shown in the figure, set the power supply voltage constant, filament resistance constant, and small bulb L marked with "6V 3W". Close the switch, when slide P of sliding rheostat moves to end a, the small bulb will light normally; when slide P moves to end C, the indication of ammeter is 0.2A
(1) Supply voltage
(2) Resistance of filament
(3) When the slide P moves to C, the slide rheostat is connected to the resistance of the circuit
(4) When slide P moves to C, the actual power of small bulb
2. (2006, Anhui Province) as shown in the figure is the working principle diagram of household electric rice cooker. R1 is the heating resistance with a resistance value of 48.4 Ω; R2 is the current limiting resistor with a resistance value of 484 [the known specific heat capacity of water is 4.2 × 103J / (kg ﹥ 8226; ℃); the boiling point of water at 1 standard atmospheric pressure is 100 ℃]
(1) When switch S is off, what is the ratio of power consumed by R1 and R2 in the circuit?
(2) When switch S is closed, what is the electrical power consumed by resistor R1?
(3) If the efficiency of converting electric energy into internal energy of water in the cooker is 84%, how long does it take at least to boil 2kg water at 20 ℃ under 1 standard atmospheric pressure?
The power supply voltage is constant, 6V, R1 = 4 ohm, R2 = 6 ohm
I think like this: using 6V for 2a, the total resistance is 3 ohm, but what's wrong with my idea?
Unable to find the map, unable to open the web page
The function f (x) = logax, G (x) = loga (2x + m-2) is known,
Where x belongs to [1,2], a 〉 0 and a is not equal to 1, m belongs to R. (1) when m = 4, if the function f (x) = f (x) + G (x) has the minimum value 2, find the value of a: (2) when 0 〈 a 〈 1, f (x) 2g (x) is constant, find the value range of real number M
(2) When 0 ﹤ a ﹤ 1, if 0 ﹤ a ﹤ 1, f (x) ≥ 2g (x) holds, that is, if x belongs to [1,2], X ≤ (2x + m-2) ^ 2 holds
When Δ ≤ 0, that is, (4m-9) ^ 2-16 (m-2) ^ 2 = 16m ^ 2-72m + 81-16m ^ 2 + 64m-64 = - 8m + 17 ≤ 0
M ≥ 17 / 8 2. When Δ > 0 m
(39 minus 27 molecules 26) multiply by 1 / 13!
(39 minus 27 elements 26) times 1 / 13
=39x1/13-26/27x1/13
=3-2/27
=79/27
It is known that the polynomial MX & sup3; + 3nxy & sup2; - 2x & sup3; - XY & sup2; + 2x + y of x.y does not contain a cubic term, so we can find the value of 2m + 3N
mx^3+3nxy^2-2x^3-xy^2+2x+y
=(m-2)x^3+(3n-1)xy^2+2x+y
If it does not contain cubic terms, it is concluded that:
m-2=0
3n-1=0
M = 2, n = 1 / 3
2m+3n=4+1=5
How many angles are there in one 360 degree minute six
7
The value of determinant (first row: 0 000 - 1; second row: 0 0 - 2 0; third row: 0 - 3 00; fourth row: - 4 000)
Swap the first and fourth columns, add a negative sign, and then swap the second and third columns. Negative leads to positive,
The result is (- 1) × (- 2) × (- 3) × (- 4) = 24
Divide a number by 18 and 54, and the quotient is exactly an integer. The maximum of this number is?
What is the minimum number of wrong questions? The minimum number is 54
The maximum geometric multiple of 54 is OK all the time
(x + 1) / (x ^ 3 + 1) x tends to - 1 to find the limit
It's equal to one third. The numerator and denominator are derived separately, and then x = - 1 is brought in
Simple calculation: 2 / 9 of 73 and 17
Let's divide 2 / 9 by 17, which is 34 / 9, and then add 73, which is 691 / 9
RELATED INFORMATIONS
- 1. Exercises of Ohm's law in Physics 1. Observe the name plate of the sliding rheostat. What are the words on it? What do they mean? 2. Observe the structure of the sliding rheostat. How many leads does it have? Which part of the sliding rheostat is connected to each lead? 3. Characteristics of resistance in series circuit?
- 2. All formulas of physics, including deformation formula
- 3. Summary of physics formula in grade eight
- 4. The physics concept formula of the second half of the eighth grade The mid-term exam will be held soon. The formula and concept of electric power will be summarized by experts. Thank you
- 5. A and B practice running on the circular track. A runs one circle in one minute on average, B runs one circle in 1.2 minutes on average. If they run in the same direction at the same time, how many minutes will it take for them to meet for the first time?
- 6. Given that a is less than 0, then the point P (- the square of a-2,2-a) is in the () quadrant?
- 7. The result of factoring polynomial 2mx2-4mxy + 2my2 is______ ．
- 8. A fruit company urgently needs to transport a batch of fruits that are not easy to store from city a to city B for sale. There are three transportation companies to choose from. The information provided by the three transportation companies is as follows: transportation unit & nbsp; & nbsp; transportation speed (km / h) & nbsp; transportation cost (yuan / km) & nbsp; packaging and handling time (H) & nbsp; packaging and handling cost (yuan) & nbsp; & nbsp; Company a & nbsp; 60 & nbsp; 6 & nbsp; 4 & nbsp; 1500 & nbsp; company B & nbsp; 50 & nbsp; 8 & nbsp; 2 & nbsp; 1000 & nbsp; company C & nbsp; 100 & nbsp; 10 & nbsp; 3 & nbsp; Answer the following questions: (1) if the total cost of packing, loading, unloading and transportation of company B and company C is twice that of company a, find the distance between city a and city B; (2) if the distance between city a and city B is s (km), and the loss of this batch of fruit in the process of packing, loading, unloading and transportation is 300 yuan / hour, then the total cost to be paid by the fruit company (the sum of packing and handling expenses, transportation expenses and loss) is the smallest. Which transportation company should be chosen?
- 9. Factorize the following formulas: ① 16x^2-49y^2 ② 4+12(x-y)+9(x-y)^2 ③ x^3-9x ④ a^4-2a^2 b^2+b^4 ⑤ (a^2-a)^2-(a-1)^2 ⑥ 16x^4-1 Fill in the blanks: ① 3^2004 -4*3^2003 +10*3^2002=_______ ② 3^n+2 -4*3^n+1 +10*3^n=_______ There is also a question about factoring 16-(2a+3b)^2
- 10. In order to estimate the number of yellow sheep in a certain area, 20 yellow sheep were captured and marked respectively, and then put back. After the marked yellow sheep were completely mixed with the Yellow sheep group, 40 yellow sheep were captured for the second time, and two of them were found to have markers. Therefore, it is estimated that there are yellow sheep in this area______ ．
- 11. 25
- 12. Talk about the knowledge about current, voltage, resistance and Ohm theorem in the second semester of junior high school physics, and how to analyze the circuit,
- 13. The application of Ohm's law in Physics Connect a 5-ohm resistor R1 and a 15 ohm resistor R2 in series, and connect them to a 6V power supply. What is the current in the series circuit? (the format should be standard ~)
- 14. Or is it about Ohm's law If the voltage at both ends of a resistance is 10V and the current passing through it is 50mA, the resistance is Ω. If the voltage at both ends of the resistance increases by 5V, the current passing through it is a. if there is no voltage at both ends of the conductor, the current passing through it is a and the resistance of the conductor is Ω
- 15. Electrician Lao Li urgently needs one 30 ohm resistor and one 5 ohm resistor when repairing electrical appliances, but he only has five 10 ohm resistors on hand. Please find a way to help Lao Li solve the problem immediately: ()
- 16. Second grade physics "Ohm's law" questions There are at least 10 choices, 10 blanks and 4 calculations
- 17. The contradiction between Ohm's law and Joule's law With the same rated voltage, the higher the rated power is, the smaller the resistance is, and the more heat is generated per unit time. However, according to Joule's law, with the same current, the larger the resistance is, and the more heat is generated per unit time There seems to be a contradiction between the two. Why? Experts help~~~~~~~~
- 18. The correct understanding of the deformation formula r = UI of Ohm's law is () A. R is directly proportional to u. B. R is inversely proportional to I. C. r has nothing to do with u and I. D. all the above statements are correct
- 19. The calculation formula of Ohm's law
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