Class: _ _ _ _ _ _ Name: _ _ _ _ _ Seat number: _ _ _ _ _ _ Score: _ _ _ _ _ _ _ _ _
First, multiple-choice questions (3 points for each small question, 30 points for * * *)
1. A student measured the thickness of an MP3 with a scale with a scale value of1mm. The four measurement results are as follows: 10. 1mm, 10.2mm, 10.3mm, 12.9mm, per magazine.
A.10.875mm B.10.9mm C.10.2mm D.10.20mm.
2, about the error problem, the following statement is correct ().
A. the error is an error in the experiment; B. a serious attitude can avoid mistakes;
C. Using accurate tools and correct measurement can avoid errors; D. mistakes are inevitable and can only be reduced.
3, scientists generally have to think about the problem ()
A. Ask questions, conjecture and hypothesis, make plans and design experiments. B. Exchange and cooperate, conduct experiments and collect evidence.
C. analysis, demonstration and evaluation D. the above are generally involved.
4. Among several statements about sound phenomena, the correct one is ().
A. as long as the object vibrates, it will certainly hear the sound. B. as long as the sound appears, you will definitely hear the echo.
C. echo is produced by the vibration of an object. Sound travels slower in air than in water.
5. "Pumbaa, it's time to eat!" Hearing the sound, Pumbaa, who is doing his homework, knows that his mother is calling him without looking up. The main basis for his judgment is ().
A. tone b loudness c timbre d frequency
6. We live in a world of sound. The following sounds: (1) the roar of machines in the factory workshop; (2) The performance of Peking Opera in the theater; (3) The chirping of birds in the park in the morning; (4) the sound of the electric drill when decorating the house; (5) firecrackers at the wedding; (6) The murmur of mountain streams. Belong to the noise is ()
A.( 1)(3)(4)b .( 1)(2)(5)c .( 1)(4)(5)d .( 1)(4)(5)(6)
7. When a beam of light hits a plane mirror, when the incident angle increases by15, the reflected light and the incident light are just perpendicular, and the original incident angle is ().
A.30 B.45 C. 15 D.60
8, the following statement about light phenomenon, the correct is ()
A. the light always travels straight. B specular reflection obeys the law of light reflection, while diffuse reflection does not.
C. The image formed by pinhole imaging is the same size as the object, and it is an inverted virtual image.
D. the rearview mirror of the car is a convex mirror, which can expand the field of vision.
9. Knock on one end of a long iron pipe filled with water, and the number of times people at the other end can hear the knocking is ().
A. 1
In the 10 and 100 meter races, if the timekeepers of Party A and Party B record the performance of the same athlete according to the smoke and gunfire of the starting gun respectively, then ().
The result of a record will be more accurate. The results recorded by B will be more accurate.
C the results recorded by both parties are equally accurate. It is impossible to determine whose record is accurate.
II. Fill in the blanks (65438+ 0 for each blank, ***28)
1 1. Fill in the following measurement results in the appropriate units: Jay Chou is about1700 _ _ _ _ _ _; It takes about 240 _ _ _ _ for He Jiong to sing "Gardenia Blossoms".
12, the measured length of an object is 1.2 180m, and the scale value of the scale used is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
During the spring outing, the students saw: ① fish in the water; (2) the bright spot in the shade at noon; (3) the reflection of trees on the shore in the water.
(4) your own shadow in the sun. (5) The water in the pool reflects the bright moon. In the scenery they see, the phenomenon of light reflection is _ _ _ _ _ _; Belong to the phenomenon of linear propagation of light is _ _ _ _ _. (Fill in the serial number above)
14. Firecrackers make a sound when they explode. The noise emitted by firecrackers of different sizes is different in _ _ _ _ _ _. Some girls have sharp voices. This is because the vocal cords vibrate _ _ _ _ _ _ _ _ _ _ _, and the sound is _ _ _ _ _ _ high.
15, ultrasound and infrasound can't be heard because their _ _ _ _ _ _ _ is too big or too small. By hearing, we can't find flying butterflies because of _ _ _ _ _ _ _ _ _ _ _ _ _, but we can find flying mosquitoes because of _ _ _ _ _ _ _ _.
16. The condition for light to travel in a straight line is _ _ _ _ _ _ _ _ _ _ _. When lightning strikes, we always see the lightning first, and then hear the thunder, because _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
17, at 1.5m in front of the mirror, the image formed in the mirror is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
18, some cities prohibit setting off firecrackers, which is to reduce noise through _ _ _ _ _ _ _ _ _ _ _ _ _; When setting off large firecrackers, some people plug their ears with their fingers in order to _ _ _ _ _ _ _ _ _ to reduce noise; In the snowy season, it is very quiet outdoors, which is to reduce the noise of _ _ _ _ _ _ _ _ _ _ _.
19, Xiao Liang once observed that the image of the license plate number of a Mercedes-Benz car in the plane mirror was "8 1-0 1", so the license plate number of the car was _ _ _ _ _ _ _.
20. Put the sounding alarm clock in the glass cover, and put the soft foam plastic between the alarm clock and the glass cover base. Gradually pump the air out of the range hood, and the alarm clock you hear changes in _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. The above phenomenon shows that the sound of the alarm clock can spread in _ _ _ _ _ _ _ _
2 1, the topic contains the physical knowledge of sound characteristics, please complete it.
(1) "deafening" means that the sound is _ _ _ _ _ _ _; (2) "pleasant to hear" means that the voice is _ _ _ _ _ _ good;
22, doctors can use ultrasonic vibration to remove stones in the human body, which shows that sound can spread.
Three, drawing questions (*** 13 points)
23. Draw the reflected light in figure (a). (2 points)
24. As shown in Figure (b), S is a point light source, S' is an image formed in a flat mirror, and P is the position of the eye. Try to determine the position of the plane mirror in the drawing, and draw the light emitted from point S and reflected by the plane mirror to point P. (5 points)
25. As shown in Figure (c), the light emitted by the same luminous point S is reflected by a plane mirror to form two reflected rays. Please draw the position of the starting point .. (3 points)
26. Xiao Ming wants to shoot a beam of sunlight vertically into a deep well, making an angle of 300 with the horizontal plane, as shown in figure (d). Please draw the reflected light in the picture and mark the reflection angle. (3 points)
Figure (a) Figure (b)
Figure (c) Figure (d)
Four, experimental inquiry questions (*** 17 points)
27. 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 my classmates, I put forward the following conjecture:
Guess 1. The pitch of the sound produced by the strings may be related to the cross-sectional area of the strings;
Guess two. The pitch of the sound produced by the strings may be related to the length of the strings;
Guess 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 strings listed in the table below. Because the pitch depends on the vibration frequency of the sound source, they borrowed an instrument that can measure the vibration frequency to do the experiment.
The number A B C D E F G H I
Material copper copper copper steel nylon nylon
Length (cm) 60 60 60 80100 80 80100
Cross-sectional area (mm) 0.760.891.020.760.761.021.02.
(1) in order to verify the conjecture 1, the string numbered _ _ _ _ _ _ _ _ _ _ _
In order to verify conjecture 2, the string numbered _ _ _ _ _ _ _ _ _
The material specifications in the table are not completely filled in. In order to test conjecture 3, you must know this item. Please fill in the missing data in the form. (8 points)
(2) 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 operation is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _.
__________________________________________________________________。 (3 points)
28. After studying acoustics, a classmate expressed doubts about the authenticity of the allusion of "filling a vacancy". He believes that from an acoustic point of view, Mr. Nan Guo, who doesn't know music, will be found as soon as he plays the flute and can't "make up the number". What is this classmate's reason? Talk about your point of view. (6 points)
Verb (abbreviation of verb) calculation problem (6 points for each problem, *** 12 points)
29. The ship emits ultrasonic waves to the seabed at a depth of 4500 meters. If the propagation speed of ultrasonic wave in seawater is1500m/s, find the time when the ship receives the ultrasonic echo.
30. If the echo reaches people's ears at least 0. 1s later than the original sound, and the speed of sound in the air is 340m/s, how far away from the obstacle should people want to hear the echo of their call?