Physics examination questions at the end of eighth grade
Volume (1) Multiple choice questions (full score 30 points, 2 points for each small question)
() 1. The following statement about light phenomenon is correct:
A, the propagation route of light is always straight
B specular reflection obeys the law of light reflection, while diffuse reflection does not.
C. The image formed by pinhole imaging is equal to the size of the object and is an inverted virtual image.
D, the camera uses the principle of convex lens inversion to reduce the real image.
() 2. The following are some examples of light phenomena collected by Xiaoli from her life. The following statement is correct:
A. Figure A Looking at an object through a magnifying glass, the object is always magnified.
B. The color of the TV picture in Figure B is composed of three colors: red, green and blue.
A lenticular lens can only converge light parallel to the main optical axis.
D. Experienced fishermen in Dudeng pointed to the harpoon they saw when fishing with a harpoon.
() 3. The following is a study on the evaporation speed of alcohol under different conditions, in which the evaporation speed and surface area of alcohol can be best explained as follows.
Close is:
A. Alcohol with different temperatures is put in the same container and in the same place, and the evaporation rate is different.
B the evaporation rate of alcohol at the same temperature in the same container and in different places is different.
C the evaporation rate of alcohol at the same temperature is different when it is placed in containers with different calibers and in different places.
D. Alcohol at the same temperature is put in containers with different calibers and in the same place, and the evaporation rate is different.
() 4. As shown in figure 1, when the switch S is closed, it is found that the light is not on. When an electrician uses an electric probe to test points A, B and C, all neon tubes in the electric probe emit red light, while those in the electric probe do not emit light when measuring point D.. The fault is:
A. the filament of light bulb l has been broken.
B. Poor contact of switch S D.
C. the connector of connection point a falls off.
The line between d.cds (excluding point c) is broken somewhere.
B.C.
() 5. The following knowledge structure is correct:
Loudness fixed
The unique tone of a.b.
tone colour
liquid gas
C the following circuit elements are connected with their corresponding functions:
Continuous power supply
Connect the wires or cut off the power supply.
The switch works by current.
Connect parts with electrical appliances.
Specular reflection
show
D. optical propagation convex lens imaging mode
optometry
() 6. As shown in figure 1, the image of ice melting to water boiling (in standard atmosphere),
This statement is correct:
A. As can be seen from the figure, its melting point is100℃;
B and BC are solidification processes and are in the state of solid-liquid existence;
C. As can be seen from the figure, ice is amorphous.
D. DE section is a boiling process, and water needs to absorb heat but the temperature remains the same.
() 7. Drawing problem: One of the following optical drawing errors is:
Figure 1
A the reflected light of parallel light hitting the convex mirror and the refracted light of light hitting the water surface from the air.
C. the convex lens will condense light. D. a beam of light is reflected after hitting the plane mirror.
() 8. The following is the experimental process of a classmate measuring the temperature of liquid with a thermometer. One of the mistakes is:
A. Observe the thermometer to be used and know its range and dividing value.
B, fully contacting the glass bulb of the thermometer with the liquid to be measured;
Take the thermometer out of the measured liquid and read it under the light.
Put the thermometer into the measured liquid before reading.
() 9. The following are several steps for Xiao Yu to learn the "convex lens imaging law", among which it is unnecessary:
A. measure the image distance with a scale.
B. Move the light screen until a clear candle image appears on the screen.
C. a thermometer measures the temperature in the laboratory.
D, adjusting the heights of the convex lens, the shading plate and the candle flame so that their centers are approximately at the same height.
() 10. Look at the picture and ask questions. The wrong statement is:
A. Figure A shows that the propagation of sound needs a medium.
Figure A shows that gas can transmit sound.
C Figure B shows that when reading with a thermometer, the line of sight should be level with the upper surface of the liquid column.
D. Figure C is an experiment to study the reflection law of light.
() 1 1, "In hot summer, teapots made of clay are often used in farmhouses to enjoy the cool, because the water it carries cools faster than ordinary teapots". According to this phenomenon, you can ask questions:
A. the relationship between timbre and object material
B. Relationship between thermal insulation performance of objects and materials
C. Relationship between thermal insulation performance of objects and temperature
D. the relationship between the thermal insulation performance of an object and time
() 12, combined with the above questions, the following guess is correct:
A. timbre has nothing to do with the material of the object.
B. The higher the temperature of the object, the better the heat insulation performance.
C. the thermal insulation performance of an object is related to the material.
The shorter the d time, the better the thermal insulation performance of the object.
() 13, about the physical knowledge of refrigerator use, the statement is wrong:
A.there is a radiator behind the refrigerator. If it is too close to the wall or furniture, it will affect heat dissipation and increase power consumption.
The refrigerator is cooled by the sublimation of freon.
C. When the current through the refrigerator is too large, it will lose its balance and even burn out.
D The color of the refrigerator shell is mostly white, because white is more conducive to the heat insulation of the refrigerator shell, which can transfer the heat in the environment to the refrigerator as little as possible.
() 14, the statement about the research method is incorrect:
A comparative method: study the similarities and differences between specular reflection and diffuse reflection.
B. model method: study the propagation path of light and introduce light.
C. conversion method: to find out the current, refer to the water flow.
D. control variable method: study the influencing factors of evaporation rate.
() 15. In daily life, the following practices are feasible:
A. communicate loudly with classmates on the bus
B. When the sun is shining, use a small mirror to reflect the sun into the eyes of your classmates.
C. After going to physical education class in summer, sprinkle some water on the classroom floor to cool down.
D. When the light is strong, turn off the lights in the classroom immediately.
Volume 2 Non-multiple choice questions (full score: 70 points)
1. Optical knowledge in automobile: (full mark of this question 10, and ***3 small questions)
With brown glass, it is difficult for pedestrians to see the faces of people in the car. The tawny glass can reflect some light and absorb some light, so the light penetrating into the car is very weak. In order to see the passenger's face clearly, it is necessary to reflect enough light from the face and transmit it to the outside of the glass. Because the light inside the car is weak and there is not enough light to transmit, it is difficult to see the passenger's face clearly.
Except for buses, the front windows of most cars are inclined. When the front glass of a car is tilted, the passengers in the car are reflected to the front of the car by the glass, but the pedestrians on the road can't appear in the air above, so that the image of the passengers in the car is separated from the pedestrians on the road, and the driver will not have an illusion. The front window of a bus is much higher than that of a car. Even the vertically installed front window looks the same height as the window, and pedestrians on the road cannot appear at this height, so drivers will not confuse the image of passengers outside the window with pedestrians on the road.
1. The tawny glass on the car can only transmit colored light, and the sky seen through it is colored.
2. Draw an inclined glass window to describe the objects in the car.
3. We also know other optical knowledge in automobiles: (point out two points)
①
②
Second, the boiling of water: (this question is full of 23 points, ***5 small questions)
One day, Xiao Ming was boiling water at home. After a while, he wanted to measure the water.
Temperature, so he found a thermometer at home, as shown in Figure 2.
1. It observes that the scale value of the thermometer is-,and the current indication is. After putting it in the water, Xiao Ming began to read, as shown in Figure 3.
Xiaoming made many mistakes in this operation. Please point out two of them: Figure 2 and Figure 3.
Error ①:
Error ②:
3. If Xiaoming finally improves and successfully completes the graphic experiment, and records the water temperature 1 minute to get the data in the following table, please establish full coordinates on the graphic grid paper and draw the "temperature-time" diagram.
It can be concluded from the chart that the boiling point of water is
After staying by the fire for a while, Xiao Ming found that the sleeves of his black coat were much hotter than those of his white pocket. What happened? Is it because objects have different heat absorption abilities? Xiao Ming wants to know whether objects of different colors have different heat absorption abilities. So he did the following experiment: put in the same amount,
Water with the same temperature is poured into two mineral water bottles respectively,
Wrap the bottle with white paper and black paper respectively (as shown in Figure 6).
Figure 6
Then put the two bottles in the sun and measure the water temperature in the bottles every 3 minutes. After half an hour's experiment,
The water temperature changes of the two bottles obtained by Xiao Ming are shown in the following table:
Sunshine time (minutes) 0 369121518 2124 27 30
White paper bottle water temperature
23 24 25 25 26 27 27 28 29 29 30
Water temperature of black paper bottle
(0C)23 25 26 27 28 29 30 3 1 32 33 34
Xiao Ming analyzed the above experimental data and reached a preliminary conclusion.
According to what you have just read, please answer the following questions:
(1) Xiaoming's conclusion is: ————————————————————
People often wear dark clothes in cold winter and light clothes in hot summer. Please explain it with the conclusion you just explored.
③ What is the application of this conclusion in daily life? Please give an example:
(4) In the process of this inquiry, the scientific research methods used by Xiaoming are: ————————————————————————————————————————————————————————————————————————.
⑤ In this inquiry process, the inquiry elements that Xiaoming experienced are:,,,
、 、
Third, the comprehensive question of electricity: (the full score of this question is 20 points, and ***4 small questions)
1. In the laboratory, Kobayashi and Komatsu are doing electrical experiments. As shown in Figure 7, the A end of the wire has not been connected, and Kobayashi thought of such a problem:
(1) If the ammeter is to measure the current normally, the A terminal should be connected to the _ _ _ _ _ terminal.
(2) If terminal A is connected to terminal E, the expected situation is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
2. Komatsu wants to form a series circuit with the components in Figure 8, and let the ammeter measure L2 current. Please help him.
(1) Complete the circuit diagram
(2) Connect the physical circuit
(3) As shown in Figure 9, the current representation number is _ _ _ _ _ _ _ _ _, Then the current through L 1 is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Fourth, the application value of sonar (full mark of this question 17, ***4 small questions)
With the development of modern science and technology, people have mastered many cutting-edge and advanced detection technologies. Such as radar, you can find enemy planes hundreds of kilometers away; Infrared telescopes can find hidden enemies in the dark; Satellite remote sensing technology can scan the whole earth's surface in a few hours; Radio telescopes can observe distant space. But why not use these advanced technologies in water and still use backward sonar?
It turns out that seawater can attract electromagnetic waves, so radar is useless. The heat absorption capacity of seawater is too strong, and infrared technology is useless; Water has poor light transmission ability, but strong light absorption ability, so optical observation equipment such as telescopes can not be used. Especially in the deep sea, it is dark and nothing can be seen. The searchlight will be exposed again. But the sound transmission ability of seawater is much stronger than that of air. Sonar technology came into being. Sonar sends out bundles of sound signals with different frequencies, and then uses special equipment to receive and analyze the reflected signals. This is like installing a bat's ear, and the surrounding situation is clear at a glance.
Ultrasonic radar can also detect clouds. Ground equipment emits beams of ultrasonic waves to the clouds, and the height of the clouds can be calculated according to the reflection time. Then the frequency change of echo is analyzed, and according to the principle of Doppler effect, the drift speed of cloud in the air can be measured. Therefore, sonar technology still occupies an irreplaceable position in its special field.
By reading the above text, please answer the following questions:
1, sound is generated by an object, and the propagation speed in the air of 15℃ is, and the frequency range of sound that people can hear is HZ.
2. What are the applications of sonar technology?
This essay introduces an example of sound transmission. We also learned that using sound can also spread. Can an experiment be designed to prove the correctness of the latter view?
Reference answer:
Volume (1) Multiple-choice questions: (The full score of this question is 30 points, and each small question is 2 points)
1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15
D B D D A D B C C B B C B C D
Volume 2 Non-multiple choice questions (full score: 70 points)
1. Optical knowledge in automobile: (full mark of this question 10, and ***3 small questions)
1, Tan Hei 2 points
2, as shown in Figure 2.
3.( 1) The reflector in the automobile headlight is concave mirror: it uses concave mirror.
It can reflect the light from the light source at its focus into parallel light.
Made of the nature of ejection. 3 points
⑵ The rearview mirror outside the driver's cab is a convex mirror: it is used for people to see.
The object is small, the observation range is wider, and the driving safety is guaranteed. 3 points
Second, the boiling of water: (this question is full of 23 points, ***4 small questions)
1, 0. 1c37.80c2 point
2.( 1) The thermometer is not placed correctly and should be hung in liquid.
(2) When reading, the line of sight should be parallel to the liquid column for 2 points.
3. As shown in Figure 2-4.
4,980C1point
5.① Conclusion: Dark objects can absorb the heat released by the sun well. Two points.
② Description: Because the temperature is low in winter, people need to keep their body temperature, so
Wearing dark clothes not only does not cause fever, but also absorbs sunlight well.
Hot; In summer, the temperature is high, and the body's heat needs to be released, so there is no need for exposure.
It is hot, so wearing light-colored clothes can reflect the heat of the sun well. Two points.
(3) Application example: Solar hot water and gas have black surfaces. Two points.
(4) Control variable method, conversion method 2 points.
⑤ Finding problems, asking questions, guessing, conducting experiments, inductive analysis and drawing conclusions: 6 points.
Third, the comprehensive question of electricity: (the full score of this question is 20 points, and ***4 small questions)
1, 1B2, ② short circuit, 3 points will be deducted for burning out the power supply and ammeter.
2、
(1) Point as shown in Figure 3-4.
② As shown in Figure 4.5.
Figure 3
③0.52A 0.52A 0.52A 6 points
Fourth, the application value of sonar (full mark of this question 17, ***4 small questions)
1, vibration, 340m/s, 20-20000 6 points.
2, can detect the seabed, can calculate the height of the cloud, can measure the speed of cloud drift in the air 3 points.
3, information energy 4 points
Remove the bottom of the empty tank, cover it with rubber film and fasten it with rubber band. Put a lighted candle at the other end and knock on the rubber film against the flame, and you will find that the flame is shaking. Prove that this conclusion is correct. 4 points
Reference answer:
Volume (1) Multiple-choice questions: (The full score of this question is 30 points, and each small question is 2 points)
1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15
D B D D A D B C C B B C B C D
Volume 2 Non-multiple choice questions (full score: 70 points)
1. Optical knowledge in automobile: (full mark of this question 10, and ***3 small questions)
1, Tan Hei 2 points
2, as shown in Figure 2.
3.( 1) The reflector in the automobile headlight is concave mirror: it uses concave mirror.
It can reflect the light from the light source at its focus into parallel light.
Made of the nature of ejection. 3 points
⑵ The rearview mirror outside the driver's cab is a convex mirror: it is used for people to see.
The object is small, the observation range is wider, and the driving safety is guaranteed. 3 points
Second, the boiling of water: (this question is full of 23 points, ***4 small questions)
1, 0. 1c37.80c2 point
2.( 1) The thermometer is not placed correctly and should be hung in liquid.
(2) When reading, the line of sight should be parallel to the liquid column for 2 points.
3. As shown in Figure 2-4.
4,980C1point
5.① Conclusion: Dark objects can absorb the heat released by the sun well. Two points.
② Description: Because the temperature is low in winter, people need to keep their body temperature, so
Wearing dark clothes not only does not cause fever, but also absorbs sunlight well.
Hot; In summer, the temperature is high, and the body's heat needs to be released, so there is no need for exposure.
It is hot, so wearing light-colored clothes can reflect the heat of the sun well. Two points.
(3) Application example: Solar hot water and gas have black surfaces. Two points.
(4) Control variable method, conversion method 2 points.
⑤ Finding problems, asking questions, guessing, conducting experiments, inductive analysis and drawing conclusions: 6 points.
Third, the comprehensive question of electricity: (the full score of this question is 20 points, and ***4 small questions)
1, 1B2, ② short circuit, 3 points will be deducted for burning out the power supply and ammeter.
2、
(1) Point as shown in Figure 3-4.
② As shown in Figure 4.5.
Figure 3
③0.52A 0.52A 0.52A 6 points
Fourth, the application value of sonar (full mark of this question 17, ***4 small questions)
1, vibration, 340m/s, 20-20000 6 points.
2, can detect the seabed, can calculate the height of the cloud, can measure the speed of cloud drift in the air 3 points.
3, information energy 4 points
Remove the bottom of the empty tank, cover it with rubber film and fasten it with rubber band. Put a lighted candle at the other end and knock on the rubber film against the flame, and you will find that the flame is shaking. Prove that this conclusion is correct. 4 points