Eighth grade physics first volume mid-term exam review paper? Time 90 minutes? Full score 100 points? 1. Fill in the blanks? Each question 3 points? ***36 points? 1. What if I see better than others? If it's far, that's because I stand on the shoulders of giants." This is the famous saying of the great physicist _________. On the basis of previous research, he constructed a classical physics system with epoch-making significance. The law of _____________, etc. 2. The poem "Moving at the Maple Bridge at Night" in the Tang Dynasty reads: "Hanshan Temple outside the city of Suzhou? The bell rings at the passenger ship at midnight?" Did the people in the passenger ship by the Maple Bridge hear the bell of Hanshan Temple? Is it produced because the big bell is struck? Is it transmitted to human ears through the air? Can the people on the passenger ship distinguish that the sound is a "bell" rather than a "drum" or other sounds? In fact, he is based on 3. The height of the flagpole in the school playground is about 20. The width of the eighth grade physics textbook is about 1.6. Fill in the appropriate unit. PM2.5 refers to the particulate matter in the atmosphere with a diameter less than or equal to 2.5um. Then 2.5um. =__________m. 4. As shown in the picture, press a steel ruler on the table, and let part of it extend out of the table. Use your hand to move the end that extends outside the table. Turn the steel ruler lightly and hard, and the steel ruler will make a sound. If the _______ of the steel ruler is different? Change the length of the steel ruler extending out of the table, the _______ of the sound produced by the steel ruler will be different. ? Select "pitch", "loudness" and "tone"? 5. Mid-autumn night? The bright moon is in the sky. There are stars. We walk along the tree-lined path. There is a gentle breeze. The moonlight passes through the layers of leaves and forms circular spots on the earth. On this beautiful night, have you ever thought? ⑴ The rustling of leaves is caused by the leaves? This sound comes from the sky. ⑵ The round spots on the ground are actually the fill of the moon. "Real image" or "virtual image"? This phenomenon is called in physics.

6. Xiao Ming is 1.76 meters tall and is located 3 meters in front of the plane mirror. The distance between the image and Xiao Ming is _______m. If Xiao Ming moves forward 1 meter in front of the mirror, Xiao Ming’s image in the mirror will be _______1.76 meters? Choose "greater than", "equal to" or " "Less than"? 7. The human hearing frequency range is from Hz to Hz. Sounds below Hz are called infrasound