![](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>)
The specification of an electric iron is "220 V & nbsp; & nbsp; & nbsp; 110 W". Please answer the following questions: (1) what is the normal working current of the electric iron? (2) What is the resistance of the electric iron? (3) How much heat does it produce when it is electrified for 10 minutes at rated voltage?
(1) The normal working current of the electric iron is I = Pu = 110w220 v = 0.5A. (2) the resistance of the electric iron is r = u2p = (220 V) 2110w = 440 Ω. (3) the generated heat is q = w = Pt = 110W × 10 × 60s = 6.6 × 104j. Answer: (1) the normal working current of the electric iron is 0.5A. (2) the resistance of the electric iron is 440 Ω. (3) the generated heat is 6.6 × 104j
In the experiment of exploring the relationship between current and resistance, Xiao Ming used a power supply voltage of 3V and kept unchanged, a fixed value resistor of 5 Ω, 10 Ω and 20 Ω, the range of ammeter was "0 ~ 0.6A" and "0 ~ 3A", the range of voltmeter was "0 ~ 3V" and "0 ~ 15V", and the specification of sliding rheostat was "15 Ω"; During the experiment, the indication of the voltmeter remains unchanged at 1.5V. (1) please draw the circuit diagram of the experiment in the wire frame of Figure 1. (2) the purpose of using the sliding rheostat in the experiment is not only to protect the circuit, but also to protect the circuit______ (3) when Xiao Ming replaced 10 Ω resistance with 20 Ω resistance, he found that the voltmeter could not meet the experimental requirements. Please judge according to your experience, what is the reason for this problem______ (4) please help Xiao Ming use the original equipment to improve the experiment and achieve the purpose of this experiment______ (5) after the improvement, when Xiaoming connects a 20 Ω resistor to the circuit, the voltage remains unchanged, and the current representation is shown in Figure 2
(1) The circuit diagram of the experiment to explore the relationship between current and resistance is shown in the figure. (2) in the experiment to explore the relationship between current and resistance, the voltage at both ends of the resistance should be kept unchanged. The function of sliding rheostat in the experiment is: one is to protect the circuit, the other is to keep the voltage at both ends of the resistance unchanged
In the experiment of exploring the relationship between current and voltage of resistance, Xiao Ming wants to change the voltage at both ends of resistance. The following methods are not feasible
A. Change the number of dry batteries B. change the resistance value of the resistor C. adjust the scribing of the rheostat D. adjust the voltage adjusting knob of the student power supply what is the student power supply? We are in a remote place. We don't know but don't need thousands of words
Choose B student power supply should be the power supply used by students in the laboratory, you can switch AC and DC, change frequency, change voltage and so on
RELATED INFORMATIONS
- 1. In order to explore the relationship between current and resistance, Xiao Ming replaced the 10 ohm resistance between a and B with 20 ohm resistance as shown in Figure 8. After closing the switch, the next operation should be () A. Record the indication of ammeter and voltmeter B. Move the sliding rheostat to the right C. Move the sliding rheostat to the left D. Increase the number of batteries appropriately B, why.
- 2. As shown in the figure, the light bulb L is marked with "6V 3W", and the power supply voltage remains unchanged. When the switch is closed, the resistance of the sliding rheostat connected to the circuit is 4 Ω, and l lights normally, the power supply voltage is 0_____ 5. If the total power consumed by the circuit is 3.2w by changing the position of slide plate P of the sliding rheostat, then the actual power of the small bulb is___ W A graph is a series
- 3. In the circuit shown in the figure, the power supply voltage remains unchanged. There may be faults in resistance R and lamp L. before and after the key s is closed, the position of ammeter pointer remains unchanged. The correct judgment in the following is () A. If lamp L does not light up, only resistance R is short circuited. B. If lamp L does not light up, only resistance R is open circuited. C. If lamp L lights up, only resistance R is short circuited. D. if lamp L lights up, only resistance R is open circuited
- 4. The lamp and a resistor R are connected in series and then connected in a circuit with voltage of U. the current flowing through the lamp is I, and the electric power consumed by the lamp is?
- 5. A light bulb is marked with "4V, 4W". After it is connected in series with a constant resistance R, it is connected into the circuit with the power supply voltage of 6V. When the switch is closed, measure the A bulb is marked with the words "4V, 4W". After it is connected in series with a constant resistance R, it is connected to the circuit with the power supply voltage of 6V. When the switch is closed, the measured power consumption of R is 2W. At this time, the bulb does not light normally. Regardless of the influence of temperature on the resistance value of the bulb, calculate: 1 the resistance value of the constant resistance R, 2 the incident electric power of the bulb
- 6. In order to explore the "relationship between electric power and resistance", Li Ming found two lamps L1 and L2 with the rated voltage of 6V. He connected the two lamps in series and started the experimental exploration according to the circuit shown in the figure. After closing the switch, he saw that the lamp L2 was slightly luminous, while the lamp L1 was almost not luminous. Then the relationship between the resistance R1 and R2 of the two lamps, and the rated power P1 and P2 of the two lamps was established (not applicable) Consider the change of filament resistance value with temperature) () A. R1＞R2，P1＞P2B. R1＜R2，P1＜P2C. R1＞R2，P1＜P2D. R1＜R2，P1＞P2
- 7. 1. Two resistors with the same organization are connected in series first and then in parallel, respectively in the circuit with the same voltage. What is the ratio of the total power of series and parallel?
- 8. The bulb and a resistor are connected in series to the power supply. The power of the lamp is 81w, and the power of the resistor is 9W. If the lamp is directly connected to the power supply, it will light normally Calculate the rated power of the lamp
- 9. Without changing the power supply voltage, please design a circuit diagram to change the brightness of the bulb
- 10. To enable the rheostat to control the brightness of the bulb, should the rheostat be connected in series or in parallel with the bulb It controls the brightness of the light bulb
- 11. When exploring the relationship between the current on the resistance and the voltage at both ends, what should be kept unchanged?
- 12. The resistance of a conductor is directly proportional to the voltage at both ends of the conductor and inversely proportional to the current passing through the conductor Why wrong? How to understand the relationship between resistance, voltage and current? Don't use books. It's suitable for multiple choice questions
- 13. Is the statement "when the resistance of a conductor is constant, the current is proportional to the voltage"? Those who are right should pay attention! I thought it was right, but the answer is wrong! I wonder if it should be said that when the resistance of a conductor is constant, the current in the conductor is proportional to the voltage at both ends of the conductor! I want to win your opinions,
- 14. In the experiment of studying the relationship between current, voltage and resistance, what is used to control the current in the circuit
- 15. In the experiment of exploring the relationship between current and voltage, resistance, when exploring the relationship between current and resistance, we should () A. Adjust the sliding rheostat to keep the current in the circuit constant B. Adjust the sliding rheostat so that the voltage at both ends of different fixed resistor R remains unchanged C. Make the voltage at both ends of resistance R change in multiple D. The current in the circuit should be changed in multiple during each measurement
- 16. If the voltage U and the resistance R are doubled simultaneously in a circuit, how will the power change? P = the square of (2U) divided by 2R Why is the square of (2R) divided by R
- 17. How does the change of resistance of sliding rheostat affect the change of voltage This is the eighth edition of Zhejiang Education Press. May I ask why the voltage of sliding rheostat in the circuit (series or parallel) changes? Why does the resistance of constant value resistor not change but affect the voltage? Does sliding rheostat affect the current, resistance and voltage? Another question: which factors are related to the brightness of the bulb? Current, voltage or resistance? There must be a lot of additional points!
- 18. How to change resistance current and voltage with sliding rheostat in series circuit? How to change resistance current and voltage with sliding rheostat in parallel circuit
- 19. How to change resistance, current and voltage in series / parallel circuit? The sliding rheostat changes the resistance in the circuit. How do the current and voltage at both ends of the planting resistor change? How do the total voltage and current change?
- 20. When a resistance is increased by 3 Ω, the current in the circuit becomes four fifths of the original value. If the supply voltage remains unchanged, what is the original value of the resistance?