"Joule's Law" Electric Power PPT Download

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"Joule's Law" Electric Power PPT Download

Reaching standards and consolidating

1. Multiple choice questions

1.2017·Beijing Among the following household appliances, the one that uses current heating effect as its working principle is ()

A.TV B.Electric water heater

C. Range hood D. Refrigerator

2. Figure 4-K-1 shows the experimental device for "exploring the factors that determine the amount of heat generated when current passes through a conductor." Two transparent containers are sealed with equal amounts of air, R1 = R2 = R3. When After switch S is closed, which of the following statements is correct ()

A. This experimental device is to explore the relationship between the heat generated when current passes through a resistor and the size of the resistor.

B. The currents through resistors R1 and R2 are equal

C. After powering on for a period of time, the height difference of the liquid level in the U-shaped tube on the right is smaller than that on the left

D. This experimental device uses the thermal expansion and contraction of the liquid in the U-shaped tube to reflect the amount of heat released by the resistor.

3.2018·Shaoyang A refrigerator, a computer and an electric blanket with specifications of "220 V 180 W" are connected to the same household circuit respectively. If the power-on time is the same, then the following statement is correct ()

A. Refrigerators generate the most heat

B. Computers generate the most heat

C. Electric blankets generate the most heat

D. The three generate the same amount of heat

4. As shown in Figure 4-K-2, connect the resistance wire and the copper wire with the insulation stripped in series in the low-voltage circuit powered by the student power supply. Wrap two identical pieces of paper around the resistance wire and copper wire respectively. After being energized for a period of time, the resistance wire caused the paper to burn, but the copper wire connected in series with it did not cause the paper to burn. The reason for this phenomenon is ()

A. The current passing through the resistance wire is large, while the current passing through the copper wire is small.

B. Copper wires are conductors, and conductors have no resistance.

C. The resistance of the resistance wire is much greater than that of the copper wire

D. The energization time of the resistance wire is longer than that of the copper wire

5. The current passing through a resistance wire is 2 A, and 2.64×104 J of heat is generated when it is powered for 1 minute. Its resistance is ()

A.66 Ω B.6600 Ω C.110 Ω D.220 Ω

6. Xiao Ming used an electric stove to heat a pot of water and found that the electric stove wire was broken. In order to ensure good contact, he cut off a section of both broken ends and then connected them. Use the connected electric stove to heat the same pot of water so that the water rises to the same temperature. Compared with the original electric stove, the time required will be (the power supply voltage is the same) ()

A. lengthened B. shortened C. remained unchanged D. cannot be compared

7. Among the following examples, the one that can prevent the harm of electric heat is ()

A. Electric mattress for heating

B. Electric thermal insulation device in the clothes worn by high-altitude pilots

C. There are many small holes on the motor casing

D. Electric incubator for hatching poultry

2. Fill in the blanks

8. A resistance wire with a resistance of 30 Ω is energized for 100 s, and the current flowing through it is 0.2 A. The heat generated by the current passing through the resistance wire is ________.

9. A 60 Ω resistance wire is connected to a 36 V power supply. The heat generated in 5 minutes is ________J.

10. A resistance wire with a resistance of 100 Ω and a current of 2 A generates 3.2×104 J of heat. The time required is ________s.

11. A soldering iron marked with "220 V 40 W" will generate heat of __________J when it is energized for 10 minutes at the rated voltage.

12. As shown in Figure 4-K-3, the power supply voltage remains unchanged at 6 V, resistors R1 = 10 Ω, R2 = 20 Ω, switch S is closed, and power is applied for 30 s, then the heat generated by resistor R1 is ________J.

13. In Figure 4-K-4, the power supply voltage remains unchanged, and the bulb L is marked with the words "6 V 3 W". When the switch S is closed, the bulb L emits light normally, and the ammeter indicates 0.8 A. Then the resistance R =________ Ω, the power is energized for 10 s, and the heat generated by R is ________J.

14. When the electric fan at home is working, the fan is rotating. If you touch its motor casing with your hand, it will feel slightly hot. This shows that when the electric current passes through the electric fan to do work, a small part of the electrical energy is converted into ________ energy. The size of this part of energy ________ (optional "can" or "cannot") is calculated using the formula W=UIt.

15. When a motor is operating normally, the voltage across the coil is 380 V, the coil resistance is 2 Ω, and the current in the coil is 10 A. When this motor works normally for 10 s, it consumes _________ electricity and generates _________ heat.

16. Two resistors A and B with resistances of 50 Ω and 30 Ω respectively are connected in series and then connected to the power supply. During the same time, the ratio of the heat generated by resistors A and B is ________; if A and B are connected When the resistors are connected in parallel and connected to the same power supply, the ratio of the work done by the current passing through the resistors A and B in the same time is ________.

Keywords: Free download of PPT courseware for ninth-grade physics from People's Education Edition, Joule's law PPT download, electrical power PPT download, .PPT format;

For more information about the "Electrical Power Joule's Law" PPT courseware, please click the Electric Power ppt Joule's Law ppt tag.

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Update Time: 2024-09-20

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