Proposition: Grade 8 Physics Proposition Group Revision: Junior Middle School Physics Center Group

(Total score:120; Examination time: 100 minutes)

The title number is one, two, three, total score, total score.

Take the lead

Please note that this article is divided into the first part of multiple-choice questions and the second part of non-multiple-choice questions.

The first part of the multiple-choice questions (***40 points)

1. Multiple choice questions: (2 points for each question, ***40 points. There is only one correct answer to every question. Please fill in the serial number of the correct answer in the table below. )

Title number 1 2 3 4 5 6 7 8 9 10 scorer

answer

The title is11213141516171819 20.

answer

1. The "treble" in "soprano" refers to

A. High notes B. Loudness C. Good timbre D. Bass

2. In the following experiments or examples, it can be explained that "the tone of sound is related to frequency" is

A Put some pieces of paper on the drum surface, and you can observe that the pieces of paper keep jumping when you beat the drum.

B Take a piece of cardboard and brush it between the teeth of the wooden comb. It is faster and slower once, and the sound made twice is different.

C. the mobile phone is placed in a vacuum cover. When there is an incoming call, only the indicator light flashes and the bell cannot be heard.

D. Knock on the gong surface, press the gong surface with your hand after making a sound, and the gong sound disappears.

After a heavy snow, you will feel that everything is quiet outside. Which of the following explanations do you think is correct?

A. It may be that after the heavy snow, there are fewer vehicles and less noise.

B. It may be that after the heavy snow, the earth is white and the noise is reflected.

C Maybe the snow is fluffy and porous, which can absorb noise.

D. it may be that the temperature is low after heavy snow and the noise propagation speed is slow.

When there is no other light, the green light from the stage spotlight shines on the actors wearing white shirts and red skirts, and what the audience sees is

A. the whole body is green. B.the coat is green, and the skirt doesn't change color.

C. The coat is green and the skirt is purple. D. The coat is green and the skirt is black.

5. In the following phenomena, liquefaction is

A. the water spilled on the ground dried up. On a cold winter morning, the tiles on the roof frosted.

C. On rainy days, the blackboard is wet, and even small water drops appear. D. clothes frozen outside in winter are dry.

6. In the following phenomenon, the law of melting endothermic is used.

A use dry ice to cool down when transporting food to prevent food from rotting.

B: Sprinkling water on the ground in hot weather will make you feel cool.

C. Rub alcohol on patients with fever to relieve symptoms.

D. Adding ice cubes to cola drinks will make the drinks cooler.

7. The following statements about ultrasound or its use are incorrect.

A. bats can emit ultrasonic waves. B. Ultrasonic waves do not need medium propagation.

C. the reflection of ultrasonic waves can be used to detect the depth of the ocean. D. you can check your body with a b-ultrasound instrument.

8. There is a light emitting diode in front of the TV remote control. In order to realize the remote control of TV, different signals will be sent out when pressing different keys.

A. infrared B. ultraviolet C. ultrasonic D. infrasound

9. Which of the following statements is true about sound?

A. When musical instruments are ensemble, the sounds of violin and erhu can be distinguished because their tones are different.

B: We can't hear the sound of a butterfly flying by, because its sound is too small.

C. the harder the gong is struck, the louder it is.

D. Singers sing loudly, in which "high" means high notes.

10. Look at the color TV screen with a magnifying glass, and you will see that the orderly three-color luminous areas are

A. red, green and blue. Red, yellow and blue

1 1. Make a small hole in the cardboard, look out through the small hole, and gradually get closer to the small hole to see the scenery outside.

A. Smaller B. Bigger C. Constant D. Bigger first, then smaller

12. Ultrasonic waves are inaudible sounds and have a wide range of applications. Among the following equipment, ultrasonic is used for work.

A. money detector B. microwave oven C. TV remote controller D. sonar system on submarine

13. The reason of "Peach Blossom Red" in "Peach Blossom Matches Red" is

A. Peach blossoms can glow red by themselves. B. Peach blossoms absorb red light.

C. Peach blossoms reflect red light D. None of the above statements is true.

14. The following statement about sound phenomenon is wrong.

A. The vocal organs are vibrating.

B. Sound can travel in a vacuum just like light.

C. people often use timbre to distinguish which instrument makes the sound.

D. Planting trees along the road can not only purify the air, but also reduce noise.

15. In the early morning of summer, crystal dew often appears on the grass. After the sun comes out, the dew disappears quietly. The physical changes experienced in the above process are as follows

A. liquefy first, then vaporize B. vaporize first, then liquefy.

C, sublimation first, then sublimation d, sublimation first, then sublimation.

16. Fan Zhongyan, a writer in the Song Dynasty, wrote in "The Story of Yueyang Tower": "The moon is thousands of miles away, and there are still shadows." The following understanding of the "bright moon" in the text is correct.

A. "Hao Yue" is an artificial light source B. "Hao Yue" is a natural light source.

C. "Hao Yue" is not a light source D. "Hao Yue" can absorb various colors of light.

17. As shown in Figure 1, among the following traffic signs, those belonging to environmental protection are:

18.300 years ago, Italian scientists did an experiment: hanging many bells in the room and then letting bats fly freely in the room. For the first time, there was no restriction on bats, and the bell did not ring; The second time I blindfolded the bat, the bell didn't ring; The bat's ear was plugged for the third time, and the bell in the room rang. The following problems were not studied in this experiment.

A. How do bats avoid obstacles? B.do eyes play a role in bat flight?

C. Do ears play a role in bat flight D. How does the bell sound?

19. In the laboratory, take out a thermometer from alcohol. The pointer of the thermometer changes as follows.

A. keep going up. Keep going down.

C. increase first and then decrease D. decrease first and then increase

20. Doctors use stethoscopes to diagnose patients. The following statement is correct about the function of stethoscope.

A. It can make the sound emitted by the human body pitch higher, which makes it easier to hear clearly.

B, it can increase the amplitude of sound emitted by the human body, so that it is easier to hear clearly.

C. it can reduce the dispersion of sound and make it easier to hear clearly.

D it can shorten the distance between the listener and the vocal body, thus making it easier to hear clearly.

The second part of the multiple-choice questions (***80 points)

Two. Fill in the blanks: (65438+ 0 points for each blank, ***26 points)

Scoring reviewer

2 1. Gong sounds because of its surface. Even if the astronaut knocks at the door with great force, he can't hear the gong because there is no air on the moon.

22. "Blowing" into a boiling water cup in summer can cool the boiling water, because _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

As shown in Figure 2, Xiaoming wrapped some cotton around chopsticks and made a piston. After soaking cotton with water, he inserted cotton into a plastic pipe with openings at both ends. Blowing the upper end of a pipe can make a pleasant whistle. This whistle is caused by the vibration of _ _ _ _ _ _. Pull the piston up and down to change _ _ _ _ _ _ _ (select "Tone" and "Loudness".

24. When there is lightning and thunder, you always see the flash first and then hear the thunder. This is because _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _; Xiao Ming measured it with a stopwatch. The time from seeing the flash to hearing the thunder is 3s, so the distance from where he heard the thunder is about _ _ _ _ _ _ _ m (the speed of light in the air is 3x108m/s, and the speed of sound in the air is 340m/s).

25. In the following state change phenomenon, belongs to the solidification is _ _ _ _ _ _ _ _; Belong to sublimation is _ _ _ _ _ _ _; Where ②, ③ and ⑤ are _ _ _ _ _ processes. (Select "Exothermic" or "Endothermic")

Wet clothes that are cool outdoors are dry.

(2) In summer, when the wrapping paper of popsicles is opened, you will see "white steam".

This river is covered with ice in winter.

④ The mothballs in the wardrobe will get smaller and smaller, and finally "disappear".

In the dead of winter, there is a layer of ice on the inner surface of classroom window glass.

⑥ When paving asphalt road, put the asphalt block into an iron pot to heat it.

26. Figure 3 is an image showing the melting and solidification process of solids (degree-day is℃, time unit is minutes). As can be seen from the figure, the solid is _ _ _ _ _ _ _ (fill in "crystal" or "amorphous"), and its melting process is the segment _ _ _ _ _ _ _ _ _ _ (fill in letters) on the image.

27. On February 26th, 2004, in 65438, a strong earthquake struck South Asia and Southeast Asia, which triggered a rare tsunami and claimed many lives. Later, when people cleaned up the scene, they rarely found the bodies of animals such as cats, dogs and mice. Some people speculate that _ _ _ _ kinds of sound waves may have been generated before the earthquake. Animals can hear them and escape in time, but people can't hear them.

At the Spring Festival party in 2005, a group of young girls vividly performed the "Thousand Hands Guanyin" in China Buddhist culture through exquisite dance, which gave people a beautiful edification and good enlightenment.

(1) As shown in Figure 4, the audience can't see the faces of other actors behind Tai Lihua (leading the dance), because _ _ _ _ _ _ _ _.

(2) The Buddha's light is bright and the Sanskrit sound is like silk. We can distinguish the sounds made by different instruments, because the sounds made by different instruments are different. (Please fill in "Tone", "Timbre" or "Loudness")

(3) The clouds around the stage are like heaven. In fact, it is the _ _ _ _ _ _ effect when solid carbon dioxide absorbs heat, which leads to the cooling of water vapor in the air. (change of filling state)

29. From June 65438+1October 12 to June 17, 2005, China successfully launched and recovered the Shenzhou VI manned spacecraft. A large pool was built at the bottom of the launch pad. When the rocket is launched, the high-temperature flame is sprayed downward, and a lot of heat is absorbed by water. At the same time, the bottom of the launch pad can be prevented from melting.

Xiaoming participated in the school's "survival summer camp" last summer vacation and learned a lot of knowledge and skills of survival in the wild.

(1) Get drinking water. As shown in Figure 5, put a big plastic bag on a twig with dense leaves and tie the bag tightly. With the continuous water in plants _ _ _ _ _ _ _ _ _ _ _ _ _ _ _, after a period of time, you can get edible water;

(2) You can use the shadow to identify the direction. As shown in Figure 6, at around noon, draw the running track of the shadow at the top of the vertical pole on the ground by tracing points, and find out the point A closest to O, then OA will indicate _ _ _ _ _ _ _ _ (choose "North and South" or "East and West"). The optical knowledge used in this exercise is _ _.

(3) Open-air fires generally use windproof lighters. A metal mesh cover is arranged above the air outlet of the windproof lighter. After ignition, the temperature of the mesh hood can rise to a very high temperature, so that when the flame is blown out, the gas emitted by the machine will be ignited by the hot mesh hood. To this end, what properties should the metal used to make the mesh cover have? Answer: _ _ _ _ _ _. (Answer only one)

Scoring reviewer

Three. Experiment and inquiry questions: (***54 points)

3 1.(2 points) Measure the temperature of beaker water with a thermometer. The correct method shown in Figure 7 is ......................................................................................... ().

32.(2 points) Commonly used thermometers use the principle of _ _ _ _ _ _ _ _ _ to measure the temperature, and the pointer in Figure 8 is _ _ _ _ _ _ _ _℃

33.(4 points) The measuring range of the thermometer is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

34.(6 points) In the experiment of "observing the boiling of water", an experimental group observed that the situation of bubbles rising in water is different before and during boiling, as shown in Figures 9 A and b, so _ _ _ _ in the figure is the situation before boiling of water. The experimental data recorded by the team are shown in the following table:

(1) From the recorded data, it can be concluded that the boiling temperature of water is _ _ _ _℃.

(2) The experimental results are obviously different from the boiling point of water at 100℃ standard atmospheric pressure, and the reason may be: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

35.(8 points) Xiaoming's mother always gets up early for fear that the food is too cold and affects his breakfast. In order to let his mother sleep for a while, Xiao Ming tried to make things cool down quickly. To this end, Xiao Ming made the following explorations:

Xiao Ming noticed that his mother put food in the air to cool it, and another substance suitable for cooling in the kitchen was water. Which has better thermal conductivity, water or air? To this end, Xiao Ming used two identical milk bottles, both of which contained hot milk, one in water at the same temperature as room temperature and the other in air. In order to minimize the influence of other factors, he padded two bottles with wooden blocks, as shown in figure 10. During the experiment, he regularly recorded the readings of thermometers A and B, and obtained the following data:

Time/min024681012141618

Nail indicator /℃ 70 60 53 47 42 39 37 35 34 33

Indication B /℃ 70 66 6 1 58 55 52 50 48 46 44

In the experiment (1), Xiao Ming needs to keep some of their quantities unchanged, such as _ _ _ _ _ _ _ _ _ _; (Just give one example)

(2) What is Xiao Ming's correct conclusion through his experiments? ___________________________ ;

(3) Xiao Ming analyzed the reasons for the slow cooling speed and realized that it was because the cooling speed of milk would be affected.

(4) According to the analysis in (3), Xiao Ming finally found a way to quickly cool objects with water, and by analogy, he understood the benefits of using running water spray method to cool high-temperature objects in industrial production: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

36.(6 points) As the saying goes, "Boiling water doesn't ring, boiling water doesn't ring." How can boiling water be louder than boiling water? Xiao Ming has studied this problem: Xiao Ming uses a round-bottomed iron pot to boil water on the gas stove, and uses a thermometer and a digital sound level meter (instruments for measuring sound intensity) to measure the water temperature in the pot and the sound intensity beside the pot respectively, and observe the related phenomena. The results are recorded in the following table:

water temperature

t/℃

Sound intensity

Grade/db 37.5 38.0 40.5 43.4 46.8 52.9 54.4 55.2 52.8

Phenomenon: no bubble, no bubble and stingy.

Bubbles produce a small amount of gas.

Bubble rising gas

Bubbles add a lot of gas.

Bubbles rise on the water surface to form more small bubbles, and the water becomes turbid and boiling.

rise

When the water is boiling, the pointer of the thermometer is shown in figure 1 1. Please help Xiaoming fill in the blanks in the form. According to the experiment, when the temperature is _ _ _ _ _ _, the loudness of underwater sound is the largest. Try to explain Xiaoming's problem according to the information provided by the experiment and related physical knowledge: _ _ _ _ _ _ _ _ _ _ _.

___________________________________________________.

37.(8 points) On Sunday morning, Xiao Tao was preparing to practice calligraphy. He just poured ink in the middle of the plate. Xiaohui and Xiaogang came to see him, and they went out together ... Xiao Tao went home at night and found that the ink on the plate had dried up, while the ink in the bottle without the lid hardly decreased. There are many similar phenomena in life. Please give an example: _ _ _ _ _ _ _ _ _ _. The evaporation rate of liquid may be related to the surface area of liquid. Please verify the above conjecture. The equipment provided is as follows: a glass of water, two pieces of glass, alcohol lamp, fan and dropper.

(1) Select the required equipment from the given equipment:

(2) Experimental steps:

(3) In life, water evaporation can be seen everywhere. Will the water vapor evaporated into the air stay in the air forever? In fact, the water on the earth is constantly circulating, and the water vapor in the air can become water again and return to the surface of the earth in various ways. Please write the name of a related natural phenomenon and the corresponding state change.

38.( 10) In the process of learning to play the guitar, Xiaohua found that the pitch of the sound produced by the strings was influenced by various factors, so he decided to study it. After discussing with his classmates, he put forward the following conjecture:

Conjecture 1: The pitch of the sound produced by the strings may be related to the cross-sectional area of the strings.

Conjecture 2: The pitch of the sound produced by the strings may be related to the length of the strings.

Conjecture 3: The pitch of the sound produced by the strings may be related to the material of the strings.

In order to verify whether the above conjecture is correct, they found nine kinds of strings listed in the table. Because the pitch depends on the vibration frequency of the sound source, Xiaohua borrowed an instrument that can measure the vibration frequency of the sound source for experiments.

(1) To verify the first guess, the string numbered _ _ _ _ _ _ _ _ _

(2) In order to verify the second conjecture, the string numbered _ _ _ _ _ _ _ _

(3) Some material specifications in the table are not filled in. In order to verify the third conjecture, it is best to fill in this item. Please fill in the missing data in the form.

(4) With the progress of the experiment, Xiaohua thinks that the pitch of the strings may also be related to the tightness of the strings. In order to verify this conjecture, the necessary operations are: _ _ _ _ _ _ _ _ _ _? __________________________.

(5) The inquiry experiments involved in our physical knowledge are similar to the above methods, such as _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Number material length (cm) Cross-sectional area (mm2)

A copper 60 0.76

B copper 60 0.89

Copper 60 1.02

Copper 80 0.76

E copper

F copper 100 0.76

G tie801.02

H nylon 80 1.02

I nylon 100 0.89

39.(8 points) Snow has a great influence on road traffic. After the road snow is compacted by the vehicle, the friction between the wheel and the road surface is reduced, and the vehicle is easy to slide left and right. At the same time, the braking distance of the car is difficult to control. Once the speed is too fast and the turn is too sharp, traffic accidents may occur. Expert research shows that different temperatures and different thicknesses of snow have different effects on automobile traffic. When the thickness of snow is 5 ~ 6544 and the temperature is about 0℃, cars are most prone to traffic accidents, because under this condition, the phenomenon of "freezing at night and turning into daytime" often appears on the road surface. At this time, road maintenance workers often sprinkle a lot of salt on the road surface to avoid the phenomenon of "freezing at night and daytime", that is, at the same temperature, melted ice and snow will no longer freeze, thus reducing traffic accidents.

Ask a question: why doesn't water freeze at the same temperature after sprinkling a lot of salt?

Conjecture and hypothesis: Please use your physical knowledge to make a reasonable guess about the reason of this phenomenon, and tell the basis of your guess.

Guess: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Basis: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.

Design an experimental scheme: design an experimental scheme to verify the correctness of your guess.

The main steps of the experiment:

Jiangyan city 2005-2006 school year first semester midterm exam.

8th grade's Physics Answers and Scoring Criteria

1. Multiple choice questions: (2 points for each small question, ***40 points)

Title number 1 2 3 4 5 6 7 8 9 10 scorer

Answer A B C D C D B A C A

The title is11213141516171819 20.

Answer b, d, c, c, c, c, c, c.

Two. Fill in the blanks: (65438+ 0 points for each blank, ***26 points)

2 1. Vibrating vacuum 22. Blowing accelerates evaporation, heat absorption, liquefaction and heat release. Air sound in pipe 24. The speed of light is greater than the speed of sound 1020 25. ③ ④ Exothermic 26. Crystal BC solid 27. Multiply by 28. (1) Linear propagation (2) Tone (3) Sublimation and liquefaction. Vaporization and liquefaction.

30.( 1) vaporization and liquefaction (2) straight-line propagation of north-south light in homogeneous medium (3) high melting point.

Three. Experiment and inquiry: (***54 points)

3 1.C(2 points) 32. Liquid expands with heat and contracts with cold -6 (1 point per space, ***2 points)

33.37℃ ~ 42℃ 0.1.37.539 (1minute per space, ***4 points)

34.b(2 points) (1)98(2 points) (2 points) The air pressure above the water surface is not equal to the standard atmospheric pressure (2 points).

35.( 1) Initial milk temperature (or milk quality, or water temperature and air temperature are the same) (2 points)

(2) The heat transfer performance of water is better than that of air (2 points); (3) The temperature of the surrounding environment (2 points); (4) Water keeps flowing to keep the temperature of water around the object low (2 points).

36.99( 1 min) The noise of water at 95℃ (2 points) is due to the vibration of water caused by bubbles. When water is close to boiling but not boiling, there are more bubbles, so the sound generated by vibration is louder. (3 points). (Give points as long as it is reasonable)

37. Spread the wet clothes on the hanger and dry them quickly. (2 points) (Give points as long as it is correct) (1 2) A glass of water, two pieces of glass and a dropper (2 points) (2) A. Drop the same amount of water on two pieces of glass with a dropper and make their surface areas unequal, and put them in the same environment. B.

(3) Rainfall and liquefaction (2 points) (score as long as it is correct).

38.( 1)ABC (2 points can be given for two or more correct answers, and no points will be deducted for wrong answers) (2)ADF (same as above) (3)80 1.02 (4) Change the tightness of the string (5) Relationship between evaporation speed and liquid temperature (points will be given as long as it is reasonable). (2 points for each small question)

39. Guess: The more impurities in water, the lower the freezing point of water, or the lower the freezing point of mixture. (2 points)

Basis: Road maintenance workers often sprinkle a lot of salt on the road surface to avoid the phenomenon of "freezing at night and melting at day", that is, under the same temperature conditions, the melted ice and snow will no longer freeze. (2 points) (Give points as long as it is reasonable)

The main steps of the experiment: Take the same three cups, fill them with equal volumes of water, light salt water and strong salt water, put them in the refrigerator, and measure the temperature with a thermometer every 5 minutes to see if there is any icing phenomenon. If there is icing, the order of icing is clear water, light salt water and strong salt water. (4 points) If you compare a glass of water with a glass of salt water, it is also recognized.