How do teachers prepare for the test questions before taking the unit test for Chapter 3 of 8th Grade Physics Book? Here are the test questions for 8th grade physics book chapter 3 that I have brought to you for your reference.
Eighth Grade Physics Book Chapter 3 Test Questions and AnswersA. Multiple-choice questions (12?3 points = 36 points)
1. On the phenomenon of sound, the following statements are correct ( B )
A. Objects that do not vibrate may also emit sound
B. Sound travels at different speeds in air and water
C. The only way to reduce noise is to keep objects from making noise
D.? Don't make loud noises in public **** places? is to ask people in the public **** place to speak in a lower pitch
2. May 2014 the 17th Science Fair held in Beijing, a variety of intelligent robots were unveiled, as shown in the picture is the kindergarten robot and the children's race to memorize the Tang Dynasty poems. The following statements are correct ( C )
A. The sound of the robot is not generated by vibration
B. The sound of the robot can be transmitted in a vacuum
C. The main reason for distinguishing between the robot and the children's voices is that their tones are different
D. The robot's sound propagates in the air at a speed of 3?108 m/s
3. p> 3. Stringed and wind instruments must sound differently in ( B )
A. pitch B. timbre C. loudness and timbre D. loudness, timbre and pitch
4. Square dancing is a kind of fitness activity that Chinese mothers like very much. But at the same time the sound of the square dance has caused a certain impact on the residents resting in the neighboring residential buildings. In order to respect the interests of both sides and live in harmony, which of the following methods do you think is effective and reasonable ( C )
A. Residents of the residential buildings wear an anti-noise earmuffs
B. Prohibit the square dance activities
C. Dancing amahs wear an earphone to play music
D. Noise monitoring devices are installed in the residential buildings
5.
5. The following statements are correct ( D )
A. Astronauts in space can talk to each other, which shows that sound can be transmitted in a vacuum B. The main purpose of pressing the strings in different positions on the violin is to change the loudness C. Soundproof walls on both sides of the road are to reduce the noise at the source D. Ultrasound examination of the body is the application of ultrasound in medicine
6. Generally, the walls around the auditorium are made of concave and convex like a honeycomb. Generally speaking, the walls around the auditorium are made uneven like a honeycomb, which is to ( C )
A. improve the decorative effect B. enhance the sound reflection
C. reduce the sound reflection D. increase the loudness of the sound
7. We have learned many idioms that contain sound phenomena, such as ① the wall has a ear, ② cover up the ears of the bells, ③ whisper, ④ pleasant to the ear, ⑤ deafening. These idioms describe the same sound characteristics ( D )
A.① ② B.② ⑤ C.③ ④ D.③ ⑤
8. The most reasonable way to deal with the noise generated by the vibration of the washing machine body due to the failure to put the clothes on a flat surface is to ( A )
A. Reduce the noise at the source of the sound: put the clothes on a flat surface B. Reduce the noise during the process of propagation: close the doors and windows
C. Reduce the noise at the human ear: close the doors and windows
9.? Hula? is a highly skillful form of Mongolian singing. The singer uses techniques to make the breath pound the vocal cords to form a low tone, on which he regulates the oral ****ing to form a high tone, realizing the rare phenomenon of one person singing both high and low tones at the same time. The following statement is correct ( B )
A.? Huey? Middle and high notes and low notes refer to the loudness of the sound
B.? The sound in a hooter is produced by vibration. The sound in a hooter is produced by vibration
C.? The sound in a hooter is an ultrasonic wave, and the bass is an ultrasonic wave. Mids and highs are ultrasonic and lows are infrasound
D.? The sound of a hooter is produced by vibration. In the tenor and bass in the air propagation speed is not equal
10. about the sound phenomenon, the following statements are correct ( A )
A. will be a sounding tuning fork touching the cheeks have a vibration can explore the causes of sound
B. is ringing an alarm clock in a glass enclosure, and gradually pumped out of the enclosure of the air, the size of the sound to remain unchanged
C. we often say that the alarm clock in a glass enclosure, gradually pumped out of the enclosure, the sound size remains unchanged
C. We often say that sound? is a sound that is very high in pitch, but it is not a sound that is very high in pitch. , means that it has a high pitch
D. Prohibition of honking is in the process of transmission to attenuate the noise
11. (Multiple choice) The figure is? Explore the factors affecting the pitch of the tone? The following statements are correct ( ABD )
A. By changing the length of the steel ruler out of the table to change the frequency of vibration of the steel ruler
B. Many experiments to keep the amplitude of vibration of the steel ruler is the same, the use of the control of the variable method
C. The longer the steel ruler out of the table, the faster the vibration
D. Objects vibrate fast, high frequency, high pitch of the sound
12. The pitch of the sound emitted is high
12. According to the figure, the following statements are correct ( B )
A. The elephants talk to each other? conversation? Sometimes with ultrasound, the sound is very small, humans can not hear but elephants can hear clearly
B. Quiet night beside our dog sometimes suddenly ears up and turn a few times, this may be the dog heard the sound of humans can not hear
C. Family members quietly talk to each other, the dog beside the indifference because of the? Whispering? s frequency cannot be perceived by dogs
D. Because elephants and dogs have ? vocal frequencies? there is no overlap area, so the dog's barking elephant can never hear
Second, fill in the blanks (19?1 points = 19 points)
13.In early spring, the willow tree sprouting, you can fold a willow, the skin and core twisted loose, pull out the wooden core, with a knife to the tender skin of the ends of the trimmed together, you have made a ? Willow flute? Willow flute? The pleasant sound of the willow flute is produced by the vibration of the ___air column___, and the sound is produced by blowing hard on the willow flute. Blow hard on the willow flute. The sound produced by the willow flute is ___loud___; compared with the thin and short willow flute, the sound produced by the willow flute is ___loud___. The sound of the willow flute is produced by the vibration of the air columns. The sound produced by the thin and short willow flute is ___higher___.
14. The electronic anti-theft alarm device on the car, when the car is broken into can send out an alarm to remind people that the vehicle is stolen, which is the use of sound can be transmitted ___ information ___ characteristics.
15. people in swimming, will cause the water vibration and sound, the fish will be scared away, which shows: ___ vibration of the liquid (water) can transmit sound ___. Fish hear the same conditions as people, that is, is not only to have a ___source of sound___ and the ___medium___ of the propagation of sound, but also have a normal ___ear (hearing organ)___.
16. The snoring of Xiao Xuan's father while he was sleeping reached Xiao Xuan's ears through the ___air___, affecting Xiao Xuan's rest, and this sound belongs to ___noise___.
17. At the gala, the ventriloquist imitated the sounds of some animals and musical instruments, mainly imitating the __tone__ of the sound, and the audience heard the ventriloquist's voice by __air__ propagation.
18. Beijing Olympic torch in Mount Everest, the CCTV carried out a full live broadcast. In the process of watching, careful Xiaoming found that the mountaineers, even if they climbed Mount Everest to light the torch, there is no other place like the transmission of laughter, shouting scenes. Xiaocong told him: sound can transfer __ energy __, the mountain snowpack is very fragile, shouting can cause air __ vibration __, to the snowpack will cause the snowpack __ *** vibration __, may trigger an avalanche, thus endangering the safety of people's lives.
19. As shown in the figure, with a piece of paper, respectively, contact with the same speed, the number of teeth of different rotating gears, the paper issued a sound pitch height is ___different__(fill in the ? The same? or? different?) This experiment shows that the pitch is related to the __frequency__ of the vibration of the sound source.
20. The sound of the gong is caused by the vibration of the ___ gong surface ___, when the gong sounds, press the gong surface with your hand. The sound of the gong stops. This is because __the vibration of the gong surface stops and the sound stops__.
Three, experimental questions (12?2 points = 24 points)
21. Xiaoming to explore? Whether the loudness and amplitude of sound are related? Experimental equipment: tuning fork, rubber mallet, iron stand, hard Styrofoam ball, thin wire and so on.
Steps:
(1) with a thin line attached to a hard foam ball, hanging on the iron frame;
(2) with a rubber mallet gently hit the tuning fork so that it vibrates, you can hear the sound of a smaller ___ small ___. Let the outside of one arm of the tuning fork approach and touch the ball (as shown in the figure), and you can see that the ball is bounced away from the tuning fork at a smaller angle;
(3) Tap the tuning fork hard with a rubber mallet to hear a louder ___ sound, and let the outside of one arm of the tuning fork touch the ball. The ball can be seen to be bounced off the tuning fork at a ___larger___ angle.
Conclusion: When the __amplitude__ of the vibration of the sound source is larger, the __loudness__ is larger; conversely, the __loudness__ is smaller.
22. Sound is closely related to human life. In order to recognize the sound, a practical activity group designed the following experiments to explore the sound.
Experiment 1: The tuning fork that was making sound was brought into contact with water in the sink and a splash was found.
Experiment 2: with a thin wire to hang a small bell on the lower end of the cork, and placed in a flask, gently shake the bottle, you will hear a clear ? tinkling? sound, and then remove the cork, the lit alcohol cotton balls into the bottle, to be extinguished after the fire, quickly plug the cork tightly, and then shake the bottle, hear the bottle ringing much smaller than the original.
Experiment 3: support the rear wheel of the bicycle, one hand to turn the bicycle pedals, the other hand is to take a piece of cardboard, and let one end of the piece of paper into the spokes of the rear wheel of the bicycle, with the acceleration of the speed of the wheel, the sound of the piece of paper will become more and more pointed.
The above three experiments, (1) Experiment 1 shows that: __ the sound emitting body is vibrating __; (2) Experiment 2 shows that: __ the sound propagation needs a medium __; (3) Experiment 3 shows that: __ the pitch of the sound with the frequency of vibration of the sound emitting body is related to the vibration of the faster, the higher the pitch of the sound __.
23. Nie Li students in an apiary to see many bees gathered on the hive, wings did not vibrate, still ? buzzing? and still buzzing. She is interested in the "100,000 reasons" in the book? She was skeptical about the conclusion that bees make sounds by constantly vibrating their wings. She was skeptical about the conclusion that bees make sounds by constantly vibrating their wings. Where exactly is the sound producing part of the bee?
The following is the main investigation process of Nie Li:
① Glue the wings of several bees to the board, the bees still make sounds;
② Cut off the wings of several bees, the bees still make sounds;
③ Find two small grains of black dots next to the root of the wings of the bees? The black dots were found on the bees' wing roots. , the black dots drummed up and down when the bees vocalized;
④ The bees did not vocalize when they were pierced with a large-headed needle through the small black dots of multiple bees.
Please answer:
(1) The purpose of using multiple bees in the experiment by Mr. Nie Li is to __avoid the chance of the experiment__;
(2) The conclusion that can be drawn from experiments ① and ② is that the bees' vocalization is not produced by the vibration of __twofold wings__;
(3)? A large-headed needle was used to puncture the small black spots of multiple bees? is based on the assumption that __bees may make sound by vibrating the little black dots__.
IV. Calculation questions (8 marks + 13 marks = 21 marks)
24. In August 2000, the Russian city of ? Kursk? No. nuclear submarine shipwrecked in the Barents Sea, aeronautical experts with ultrasound can detect the exact location of the nuclear submarine shipwrecked. Ultrasonic wave speed in seawater is v = 1 450 m/s, in the submarine directly above the sea surface downward ultrasonic waves, from the ultrasonic waves sent to receive the submarine's echo experienced time t = 0.146 s, the submarine sunk to the actual depth of h is about how much? (Calculation results take an integer)
Solution: ultrasound from the surface of the sea to the sunken submarine with the time t = 12?0.146 s = 0.073 s, the depth of the sea water h = vt = 1,450 m / s?0.073 s = 105.85 m?106 m
25. Read the following table in the speed of sound in a number of mediums, answer the question:
The speed of sound in some media v/(m?s-1)
Air (0 ℃) 331 Ice 3 230
Air (15 ℃) 340 Copper 3 750
Kerosene (25 ℃) 1 324 Aluminum 5 000
Water (ambient) 1 500 Iron 5 200
(1) What is the law of propagation of sound in the medium? ? (Write two)
(2) At one end of a metal tube of length 884 m, two sounds are heard at the other end, separated by a distance of 2.43 s. What is the speed of propagation of sound in the tube? What material is the tube made of? (At this time the temperature is 15 ℃)