![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
How to calculate series and parallel power How many w should two 40W bulbs in series and two 40W bulbs in parallel be?
Two 40W in series, 20W in total, two 80W in parallel
How to calculate the total power in series circuit and parallel circuit?
Calculate the corresponding total resistance. Series connection is the sum of the resistances. Parallel connection is the reciprocal of the resistances. Add and then take the reciprocal. After calculating the total resistance, calculate the power with P = u ^ 2 / R
What is the reason for the large difference in resistivity between different points of polysilicon wafer?
The resistivity of silicon wafer measured by ms203 is about 3.5, but the maximum resistivity of ingot measured by rt1000 is only about 2.2
In principle, it is normal that there is a difference in resistivity between the points of polysilicon
Since it is polycrystalline silicon, it means that there are many grains and grain boundaries. Because the size of grains is not uniform, the number of grains and grain boundaries is different in different measuring points. Because the resistivity of grain boundaries is greater than that of grains, it leads to "large difference in resistivity among points of polycrystalline silicon"
When using volt ampere method to measure resistance, a student connected the experimental circuit as shown in the figure. According to the current and voltage characteristics of the series parallel circuit and Ohm's law, we can know the result he measured
Why?
The ammeter is externally connected, and the resistance to be measured is too small
The ammeter is internally connected, and the resistance to be measured is too large
(mainly considering the resistance of ammeter and the current of voltmeter)
Ohm's law the variation of resistance current and voltage
These changes are a little fuzzy, please explain the white point
For example: function image. For example, XX increases and XX decreases, respectively listing the variation of resistance current and voltage!
What I said is, according to Ohm's law, we can list the change law of resistance current and voltage respectively!
U=RI
When u is constant, R is inversely proportional to I. the larger R is, the smaller I is. The larger I is, the smaller R is
When I is constant, u is proportional to R. the larger R is, the larger u is, and the larger u is, the greater R is
When R is constant, u is proportional to I. the larger u is, the larger I is
RELATED INFORMATIONS
- 1. In the experiment of exploring Ohm's law, the relationship between current and resistance should be explored. To keep the voltage unchanged and change the resistance, the function of slide is to adjust the resistance by adjusting the current Slide the rheostat to keep the voltage constant, so why can it keep the voltage constant? What's the principle?
- 2. Swiss astrophysicist Stephanie Udry (right) and University of Geneva astronomer Michel Meyer (left) hold a picture of the planetary system around red dwarf 581 (upper right corner) on April 24, 2007. The planet, code named "581c", is 190 trillion kilometers away from the earth and is orbiting a planet smaller than the sun and hotter than the sun It has been measured that its mass is about 5 times that of the earth and its diameter is about 1.5 times that of the earth A. The ratio of the gravitational acceleration on the surface of planet 581c to the gravitational acceleration on the surface of the earth can be obtained. B. the ratio of the first cosmic velocity between planet 581c and the earth can be obtained. C. The ratio of the circumfluence velocity between planet 581c and the earth can be obtained. D. the ratio of the circumfluence period between planet 581c and the earth can be obtained
- 3. It is known that the period of the earth's revolution around the sun is t, the distance between the earth and the sun is r, and the gravitational constant is g?
- 4. The toy car with mass M1 = 1kg moves at a uniform speed of V1 = 0.5m/s on a smooth horizontal plane. A small ball with mass M2 = 0.5kg and velocity v = 0.10m/s flies into the car and moves with the car Find the speed of the car and the ball moving together The impulse of the ball
- 5. Physics in senior two (Law of resistance) 1. For a section of iron wire with uniform thickness, the diameter of cross section is D and the resistance is R. after drawing it into a uniform wire with diameter of D / 10, what is its resistance? 2. Cut a 64 ohm uniform resistance wire into equal length n segments, and then connect it in parallel. If the resistance side is 1 ohm, what is n equal to How should I think about these two questions?
- 6. What is the difference in resistivity between single-layer graphene and multi-layer graphene
- 7. What is the unit of kgf / mm2? How to convert it to MP?
- 8. Unit conversion of MPA n / mm2 and kg / mm2 Please tell your friends how to change the above three units As long as the unit conversion is n / mm2 and kg / mm2
- 9. How many CPS is the kinematic viscosity of coal tar at 50 ℃ 100mm2 / S?
- 10. Why to measure the resistivity of resistance wire and why to use current limiting
- 11. Junior high school physics when the voltage is fixed, there is such a problem in the relationship between current and resistance: a certain voltage, the measured data of current and resistance are as follows: a group of current 0.12 a, resistance 0.6 Ω; current 0.24 a, resistance 1.2 Ω; current 0.48 a, resistance 2.4 Ω. The problem is that one group of data is patchwork, which group is it? Please help to analyze, thank you
- 12. Junior high school physics questions about the range of resistance, voltage and current As shown in the figure: (I don't want to insert the picture, just say it) the sliding rheostat is connected in series with the resistance R0, the voltmeter measures the sliding rheostat voltage, and the ammeter measures the main circuit current ——————————————————————————————————————— When the switch is closed, when the slide P of the sliding rheostat slides back and forth between certain two points, the indication range of the ammeter is 0.1.5 a, and the indication range of the voltmeter is 6 ~ 3 V. then the power supply voltage is A.6 V B.7.5 V C.9 V D.15 V
- 13. Voltage of series parallel circuit In a series or parallel circuit, what is the relationship between the voltage of the power supply and the voltage of the trunk and branch in the circuit? That is, the relationship between the voltage of the power supply and the voltage of the branch and trunk?
- 14. What is the relationship between voltage, resistance and current in series and parallel circuits? What is bigger, what will become bigger? What gets smaller, what gets smaller? And in series or parallel sliding rheostat resistance increases, the current and voltage will have what kind of change? If the resistance decreases, what will the current and voltage change? Sorry to bother you.
- 15. What instrument can measure resistance and resistivity?
- 16. The measurement and application of electric conductivity Physicochemical experiment
- 17. In the series circuit, Xiao Ming wants to explore the relationship between current and resistance in a circuit. Now there are wires, switches, ammeters, voltmeters, sliding rheostats
- 18. A circuit consists of an ammeter, a battery pack, two small bulbs (same power), a switch and several wires Connect two small bulbs in parallel and connect them to the two positive terminals of the ammeter. After the circuit is connected, close the switch. What's the consequence? It's better to have a picture On the second floor, please be more specific
- 19. There is a bulb and a 20 ohm resistance ro. The ammeter is connected in the circuit. S1 controls the bulb and S2 controls the resistance ro. When the switch S1 is closed, S2 is disconnected There is a bulb and a 20 ohm resistance RO, and the ammeter is connected in the circuit. S1 controls the bulb, and S2 controls the resistance ro. When switch S1 is closed and S2 is disconnected, the bulb and ammeter are connected in series, and the sliding rheostat is modulated to make the bulb turn on and off normally. At this time, the current indication is 0.3A. When switch S1 is opened and S2 is closed, R0 and ammeter are connected in series, and the position of sliding rheostat is unchanged, and the indication of ammeter is 0.2A, Calculate the rated voltage and power of the bulb
- 20. The solid mass increases after combustion 2. The solid mass decreases after heating with potassium permanganate They are explained by the law of conservation of mass