The first volume (multiple choice questions ***24 points)

Precautions:

1. Before the answer sheet 1, candidates must write their names and test center names in the corresponding positions on the answer sheet with pens or ballpoint pens, and mark the answer sheet with the examination room number, seat number, admission ticket number and test subjects with pencils.

2. After choosing the answer for each question, black the answer label of the corresponding question on the answer sheet with a pencil. If you need to change it, clean it with an eraser, and then choose another answer label. I can't answer it on the test paper.

At the end of the exam, please return the test paper and the answer sheet together.

1.Choice (2 points for each question, ***24 points) Only one of the four options given in each question is correct.

1. Normally, the following objects are insulators.

A. iron wire B. rubber rod C. human body D. salt water

2. China's satellite communication technology has independent intellectual property rights and is in a leading position in the world. Signals from Beijing can be transmitted to Shanghai and received by communication satellites. This signal transmission is based on use.

A. Electromagnetic wave B. Ultrasonic wave C. Infrasound wave D. Sound wave

4. In the following practice, in order to reduce the pressure, it is

A. the blade of the kitchen knife is made very thin. The railway tracks are laid on sleepers.

C. the needle of the syringe is sharp. D. One end of the straw is pointed.

5. In the following practices, those that do not meet the requirements for safe electricity use are

A. the metal shell of household appliances should be grounded. B. When using the measuring pen, hands should not touch the metal body of the pen tip.

C. hang clothes on the wire. D. When the wire is on fire, cut off the power supply first, and then put out the fire.

6. Inertia is sometimes used, and sometimes it should be prevented. In the following examples, what prevents inertia from causing harm is

A. pat off clothes and dust. Shoot a football into the goal

C. The cars on the expressway drive at the speed limit. D. The quick run-up in the long jump.

7. In the following electrical appliances, the main forms of energy conversion at work are different from the other three.

A. electric fan B. electric stove C. electric iron D. electric kettle

8. The results of Xiaoyu's "Physical Health Test" are as follows. Among them, the unit that does not meet the physical requirements is

A. mass 58kg B. height170cm C. grip strength 40kg D. "50m running speed" 8m/s.

9. When you open the refrigerator door in summer, you can see that there is "white gas" by the door. These "white gases" are caused by water vapor in the air when it is cold.

A. formed by liquefaction B. formed by vaporization C. formed by sublimation D. formed by melting

12. In the experiment of studying the imaging characteristics of flat mirror, you can see the image of the candle behind the glass plate by putting a candle in front of the glass plate. At the same time, you can see the "candle" behind the glass plate. The following statement is correct.

A. Both are images formed by light reflection.

B. both of them are images formed by light refraction.

Fill in the blanks (2 points for each question, *** 16 points)

13. The power supply voltage of domestic circuits in China is _ _ _ _ _ _ _ _ V; The voltage of the dry battery is _ _ _ _ _ _ V.

14. In daily life, we often say that the sound is "deafening", which means that _ _ _ _ _ _ _ is very loud; We can distinguish the sounds made by different musical instruments, because they have _ _ _ _ _ _ kinds of differences.

15. The propagation speed of electromagnetic wave in vacuum is _ _ _ _ _ _ _ m/s, and the higher the frequency, the longer the wavelength of electromagnetic wave.

16. At present, coal, petroleum, wind energy, hydropower and solar energy are commonly used in China, among which _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

17. From a physical point of view, two pictures in the cartoon show that _ _ _ _ _ _ _ can change the internal energy of an object. In the process of sliding down the slide, the gravitational potential energy of the child in Figure (b) will be _ _ _ _ _ _ _ _ _ _ _ _ _.

18. In chemical experiments, it is sometimes necessary to heat the substances involved in the reaction. This is to increase the temperature of the reaction substance by heating, so that the irregular movement of microscopic particles can reach the purpose of _ _ _ _ _ _ _ _ _ _.

19. Weight 38N, volume 5? SPAN & gt 10-4m3 solid metal ball is immersed in a container filled with water, and the weight of spilled water is _ _ _ _ _ _ _ n, and the buoyancy of the metal ball is _ _ _ _ _ _ _ n. 。

20. In order to transmit information, China has formed a post system since the Zhou Dynasty. Every post station was replaced by a horse. There were no gold medals, silver medals and bronze medals in the Song Dynasty, among which "gold medal" 1 passed 500 Li day and night (commonly known as 1 day and night =24 hours, 1 Li =500).