eight
_ _ _ _ _ _ _ _ _ _ m/s, the broadcasting frequency of news programs of Tianjin Radio Station is 909kHz, and the wavelength is.
1* *10 page
9. Nanchang City in 2009, as shown in Figure 4, the presence or absence of solenoid magnetism can be controlled by the presence or absence of _ _ _ _ _ _ _ _ _, and its polarity is related to the _ _ _ _ _ _ _ direction in the solenoid; If solenoid A and solenoid B are connected in series in the circuit, _ _ _ _ _ _ _ is more magnetic (choose "A" or "B" B”) 10/0. In 2009, the earth in Guiyang is a huge magnet, and there is a magnetic field around it-geomagnetic field. The Chinese nation first used the geomagnetic field to serve mankind. For example, the invention of _ _ _ _ _ _ _ _ _+01 In 2009, Guiyang City used the experimental device shown in Figure 5 to convert mechanical energy into _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
It is set for news comprehensive broadcasting, and the transmission frequency is AM954kHz and FM97.3MHz, where AM stands for _ _ _ _ _ _ _ _ _; The wavelength of the electromagnetic wave with the emission frequency of AM954kHz is _ _ _ _ _ _ _ m (the calculation result is reserved with one decimal place). 13, Lanzhou (5 minutes) 2009 is an experimental device for exploring electromagnetic induction phenomenon, as shown in Figure 6. The straight copper wire ab in the device is connected to both ends of the sensitive galvanometer through wires. When ab moves up quickly, ammeter pointer _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Or) during the experiment, the switch should be _ _ _ _ _ _ _ _ wireless Internet access and other services. These services transmit signals through _ _ _ _ _ _ (choose "ultrasonic wave", "infrasound wave", "electric wave or magnetic wave"), and their propagation speed in vacuum is about _ _ _ _ _ _ _ _ m/s, and the gravitational potential energy of water is converted into _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. The working principle of the generator is _ _ _ _ _ _ _ _. As shown in Figure 7, this is an experimental device to explore the induced current conditions. When ab moved to the right, the pointer of the electric meter was deflected to the left, and now it is necessary to deflect the pointer to the right.
_ _ _ _ _ _ _ _ _ _ _ _ _ _16, the basic principle of Chaoyang telephone in 2009 is to complete the mutual conversion of sound signals and _ _ _ _ _ _ signals through the microphone and receiver. Recently, a western country's law prohibits young children from using mobile phones, because the _ _ _ _ _ _ radiated by mobile phones will endanger human health to a certain extent; Microwave travels at the same speed as medium wave and long wave. Microwave has a short wavelength, so its frequency is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. This experiment can prove that sound needs _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Experience shows that only the voltage not higher than _ _ _ _ _ _ _ V is safe for human body. As shown in Figure 8, it is a single-phase watt-hour meter for measuring the electricity consumption of users, and its index is _ _ _ _ _ _ _ kwh.19. In 2009, only light-emitting diodes were allowed in Putian. Negative electrode flows out. As shown in Figure 9, the magnet moves left and right in the coil, and at this time, two light emitting diodes will be seen to emit light in turn. The device emits light according to the principle of _ _ _ _ _ _ _ _ _ _ _ _ _ _. What do you think of the idea of wavelet? _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ In the following statement about electromagnetic phenomena in Beijing in 2009, it is correct that A. There is a magnetic field around the electrified conductor C. The strength of electromagnet magnetism is related to the number of turns of electromagnet coil D. As long as the conductor moves in the magnetic field, it will produce induced current 3. As shown in figure 10 2009 Shanghai, it correctly indicates that the N pole of the small magnetic needle points to N N N A B.
B. the generator is made according to the principle of electromagnetic induction.
Page 3 *** 10
4, 2009 In the experimental device shown in figure 1 1, what can be used to study the conditions for generating induced current?
Figure115,2009 With the advent of the 3G era in Henan Province, we can use 3G mobile phones for wireless network login anytime and anywhere. For mobile phone wireless Internet access, the following statements are correct: A. Transmitting digital signals by electromagnetic waves C. Transmitting digital signals by ultrasonic waves B. Transmitting analog signals by electromagnetic waves D. Transmitting analog signals by infrared rays.
6. In 2009, the statements about sound and electromagnetic waves in Hebei Province were correct. Both sound and electromagnetic waves can transmit information and can spread in a vacuum. B. installing double-glazed windows in houses can reduce the impact of noise on rooms. C. "Stethoscope" can increase the vibration amplitude and loudness of human heart.
D. The voiceprint lock can only be opened when the owner speaks the code word, and the main sentence that distinguishes the sound is tone 7. In 2009, the following statements about electromagnetic waves in Jiangsu Province were correct: a. Electromagnetic waves cannot propagate in a vacuum. C. visible light is electromagnetic wave. 8. In 2009, the copper bar ab was suspended between the N pole and the S pole of the magnet with cotton thread in the experimental device shown in the figure of Jiangsu Province 12. Both ends of the copper bar are connected with the ammeter through wires. When ab cuts the magnetic induction wire, it can be observed that the pointer of the ammeter deflects. According to the principle revealed by this phenomenon, the equipment that can be made is a. electric iron C. electromagnetic relay B. motor D. generator diagram12 D. ultrasonic wave is electricity B. the propagation speed of electromagnetic wave in the air is 340 m/s.
As shown in Nanchang September 2009 13, the following experimental instruments convert electrical energy into mechanical energy when working.
Figure 9 a. ammeter B. voltmeter diagram13 c. generator D. motor
10, Guangzhou, 2009, as shown in figure 14, a conductor wrapped with insulation is wound.
Page 4 *** 10 Figure 14
Scrape the insulation layer at both ends of the wire on the nail. After connecting the dry battery, the nail A is magnetic. B. It will melt. C. Current flows through D. Both ends are attractive to the north pole of the small magnetic needle. In 2009, the infrared and visible light in Guangzhou were 1 1. A. The frequencies were equal. C. Both were electromagnetic waves. A. Radio waves. B. Electric furnaces. D. In vacuum.
12,2009 Guiyang belongs to the following electromagnetic waves.
D. water wave
13, 2009 In the following equipment in Changsha, 14 converts mechanical energy into electrical energy. In Yichang in 2009, the following statements about magnetic field and magnetic induction line are correct: a. There is a magnetic field around the magnet; C. the magnetic induction line is the magnetic field; B. Communication D. Lighting.
1 2
B there is a magnetic induction line around the magnet d, which always starts from the s pole and returns to the n pole.
15, 2009 Many newly-built residential areas in Yichang City have installed optical fiber networks, and the main uses of optical fibers are A. power transmission C. heat conduction.
R S
As shown in figure 16, 2009, Jingmen City, A is the iron block suspended under the spring, B is the iron core of the solenoid, S is the changeover switch (when S is connected to kloc-0/,the number of turns of the coil connected to the circuit is more, and when S is connected to 2, the number of turns of the coil connected to the circuit is less), and P is the slider of the sliding rheostat. ... span class =' class1' > The following methods can be adopted: a. Without changing the position of slider P, change S from 1 to 1, slide slider P to the right, slide slider P to the left, and pull out iron core B. 。
P diagram 15 R'
17, Maoming city, 2009, as shown in figure 16, when the switch s is closed and the slider p of the sliding rheostat moves to the left, the electromagnet A.b end is n pole, the weak magnetic B.a end is s pole, the strong magnetic C.a end is n pole, the strong magnetic D.b end is s pole, and the weak magnetic 18. The following statement in Linyi in 2009 is wrong: A. The magnetic field is composed of countless magnetic induction lines. B. The magnetic induction line starts from the N pole of the magnet outside the magnet and finally returns to the S pole. Divide the bar magnet into several sections, each section has N pole and S pole. D. The needle is magnetized into a small magnet while being attracted by the magnet. Page 5 * * 10 Figure 16.
19,2009 Yulin electromagnet is a solenoid with iron core, which is widely used. If we want to enhance its magnetism, the following methods are feasible: A. Reduce the number of turns of the coil C. Change the current direction in the coil B. Increase the current in the coil D. Reduce the voltage at both ends of the coil.
The main difference between the third generation digital communication technology (3G for short) and Zhanjiang 1G, 2G and 2G in 2009 lies in the improvement of voice and data transmission speed. The most direct change is the opening of videophone, which can not only hear the sound but also see the dynamic image of the other party. 3G mobile phones rely on a, electromagnetic waves, infrared rays, hair dryers, ultrasonic waves, generators and infrasound waves.
Among the following equipments in Fuzhou in 2009, 2 1 works by electromagnetic induction principle.
22. In 2009, the following equipment in Loudi had nothing to do with electromagnetic waves ... A. "Chang 'e-1" received the operation instruction from the ground command center to realize orbit change and ran to the moon. B. the car is equipped with GPS (global positioning system) to determine the driving route and distance. C after the Wenchuan earthquake, the relief workers resumed communication with the outside world by satellite phone. D. In the hospital, doctors can observe the baby in the mother's body with B-ultrasound. 23. Weifang City In April 2009, China successfully launched the second Beidou navigation satellite in xichang satellite launch center, which can provide high-precision positioning, speed measurement and time service. It uses electromagnetic wave B, ultrasonic wave C, infrasound wave D and various rays 24 to transmit information. In 2009, the mobile phone in Dezhou was one of the most commonly used communication tools for modern people. Using B, ultrasonic C, optical fiber D, air A and microwave to transmit electromagnetic waves is.
In Mianyang in 25 and 2009, electromagnetic waves played an important role in modern information transmission. The following information transmission modes are adopted: ① wired telephone ② mobile telephone ③ radio and television ④ satellite communication ⑤ network communication ⑤ optical fiber communication A.2346b.1235c.131946d.245626, in 2009, scientists in Lishui discovered that some materials have giant magnetoresistance effect. In other words, a weak magnetic field change will lead to a sharp change in resistance. According to this principle, it can be made into a battery that can store and release a lot of electric energy. B. an electromagnet that can generate a strong magnetic field through a weak current. C fuses that can be blown automatically when the household circuit is overloaded or short-circuited. D. Sensitive magnetic head capable of "reading" weak magnetic field changes and converting them into current changes. Ya 'an City, as shown in Figure 17, 2009, AB and CD are two fixed and parallel horizontal smooth metal guide rails, and the symbol "×" represents the magnetic induction line perpendicular to the magnetic field on the paper. At present, the copper bars EF and GH are placed vertically on the slide rail, which is in good contact with the metal guide rail. When external force pulls GH to move to the left, it is found that EF also moves to the left under the action of induced current. When GH is pulled to move to the right, page 6 of figure 17 *** 10.
A. the copper bar EF does not move. Copper bar EF moves to the left.
B. the copper strip EF also moves to the right. D. whether to move D. Silver is uncertain.
In 2009, the geological exploration team of Putian City found that the geomagnetic field in the area of tens of thousands of square kilometers in East China is very abnormal, and there may be a considerable amount of α -copper underground in this area. The title of the drawing is 1. In 2009, there were electrified solenoids in Henan Province, and the current direction is shown in Figure l8. Please draw two magnetic induction lines passing through point A and point B respectively. 2. In Lanzhou City in 2009, please draw two magnetic induction lines in figure 1.
Figure 18
Figure 19 iv. Inquiry and experimental problems
Figure 20
3. In 2009, Tai 'an marked the "+"-"pole of electrified solenoid power supply according to the direction of N pole of small magnetic needle in Figure 20. In 2009, an interest group in Jiangsu Province (5 points) found a ring magnet in the speaker, and they didn't know the magnetic pole distribution of the ring magnet. So several students put forward the following three conjectures: conjecture 1: the magnetic poles are horizontally distributed (for example, in Figure A, the left is the N pole and the right is the S pole); Conjecture 2: the magnetic poles are axially distributed (for example, in Figure B, the upper side is N pole and the lower side is S pole); Guess 3: the magnetic poles are distributed up and down (for example, in Figure C, the upper and lower sides are N poles, and the middle part is S poles).
(1) According to what they know, after discussion, they come to the conclusion that conjecture 3 is wrong. Do you think their judgment is based on _ _ _ _ _ _ _ _? (2) To test other conjectures, they hung the ring magnet horizontally with thin iron wire (as shown in Figure D). As a result, it is observed that the magnet can remain stationary at any position. This shows that the conjecture _ _ _ _ _ _ _ is wrong. (3) Please design a simple experiment to verify whether the residual conjecture is correct, and briefly describe your experimental scheme. Main equipment: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _; Brief practice: _ _ _ _ _ _ _ _ _ _; How to judge: _ _ _ _ _ _ _ _ _ _. Page 7 *** 10
2. In 2009, in Changsha, in order to find out what factors are related to the magnetic field strength of electromagnets, Qin Xiao students made a simple electromagnet by winding enameled wires (wires coated with insulating paint) on large nails. The following four situations were observed in the experiment.
① When the switch is closed, please mark the N pole of the magnet in Figure A; ② Compare the difference between the numbers _ _ _ _ _ _ _ _ _ and _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3. In 2009, Yichang City, as shown in Figure 23, was a hand-driven generator used in the laboratory. Connect an ammeter in series in the circuit between the generator and the bulb, slowly turn the coil, and observe the direction of the ammeter pointer swing: _ _ _ _ _ _ _. This explains _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. ② _ _ _ _ _ _ _ _ _ _ _ _ _. 4, Zhanjiang City, 2009 Figure 24 is an experimental device for "Exploring the conditions of induced current when a conductor moves in a magnetic field". When the switch is closed, the copper bar ab, ammeter and switch form a closed circuit. Xiao Ming recorded the phenomena observed in the experiment in the table below. Figure 23.
Fig. 24 The switch with conductor number ab 1 2 3 4 5 6 7 is open, closed, closed, closed, closed, closed, closed, closed and closed. Magnetic field direction, N up, S up, S up, S up, N right, up, right, left, ammeter pointer deflection direction does not deflect to the left.
(1) Xiao Ming's analysis shows that when some conductors in a closed circuit do _ _ _ _ _ _ _ _ _ _ _ _
Page 8 *** 10
(2) Comparing Experiment 2 and Experiment 3 (or Experiment 6 and Experiment 7), we know that when the direction of magnetic field is fixed, the direction of induced current is related to _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. (3) Comparing Experiment 2 and Experiment 6 (or Experiment 3 and Experiment 7), we can see that _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _. The research methods of this experiment are controlled variable method and _ _ _ _ _ _ _ _ _ _ _. In the course of this experiment, _ _ _ _ _ _ _ _ _ _ _ _ can be transformed into _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Write down the main steps to verify your guess. How did you analyze and judge the experimental results? 5. The comprehensive application problem of Guiyang in 2009 is shown in Figure 25, and the "×"1in the dotted line area is the magnetic induction line perpendicular to the paper. When the metal frame slides from the top to the bottom of the smooth insulating slope, its kinetic energy is e1; If the metal frame is replaced by a plastic frame with the same mass, other conditions remain unchanged, and the kinetic energy of the plastic frame when it slides to the bottom is E2. Please judge the relationship between E 1 and E2, and briefly explain the reasons for the judgment. (Hint: The metal frame is a conductor and has resistance) Figure 25.
Answers to electromagnetics exercises
1. Fill in the blanks 1, 3×10; 2. Static; Constant; Radio waves; 3. Atmospheric pressure; Electromagnetic induction; 4. There is a magnetic field around the charged conductor; The direction of magnetic field is related to the direction of current; 5,3× 10 ; 330; 6. Electromagnetic induction power generation; 7, ; 8, n shortens electricity; 1 1, generating electricity; 12, AM 3 14.5m magnetic induction; 9, current current b; 10, compass (or SiNa) 13, without deflection, deflects a part of the conductor of the closed circuit. When the magnetic induction wire is cut in the magnetic field, current will be generated in the conductor, and the electromagnetic wave is 3× 108. 15, dynamic and electromagnetic induction, make ab move to the left (or make the magnet move to the right); 16, high electromagnetic wave; 17, the medium (air) is in a vacuum, (other reasonable expressions are enough); 18,50, 36, 586.6; 19, electromagnetic induction generator 2, multiple-choice question 1, d; 2、ABC3，A； 4，A； 5，A； 6、B； 7，C； 8，D； 9、ABD 10，A； 1 1，C； 12，A； 13，D； 14，A； 15，B； 16，C； 17，C； 18，A； 19，B； 20，A； 2 1，C； 22，D 23，A； 24，A； ; 25，A； 26，D； 27，B； 28. B IV. Exploration and Experiment 1, (1) A magnet can only have two poles; (2) 1 ; (3) Small magnetic needle Place the small magnetic needle at different positions around the magnetic ring, and observe the directions of the two poles for many times after the small magnetic needle is stable, so as to judge the position of the magnetic pole of the magnetic ring. Page 9 *** 10, using one can save materials, but the effect is not as good as using two. When two are used, no matter whether the magnet moves to the left or right, one diode can be seen to emit light.
8 5
2. (1)N pole is at the top.
(2) b
The third/third in ten days' work
(3) D.
3. Swing from side to side; The direction of the current is changing (or the electricity generated by the generator is alternating current); Turn the coil quickly/enhance the magnetic field/increase the number of turns of the coil. (1) cutting magnetic field (or moving perpendicular to the direction of magnetic field) 4. (2) cutting magnetic field direction of conductor (or moving direction of conductor) (3) When the direction of cutting magnetic field of conductor (or moving direction of conductor) remains unchanged, the direction of induced current is related to the direction of magnetic field (4) conversion. The magnitude of the induced current of the generator (or mobile microphone) (5) may be related to the moving speed of the conductor cutting the magnetic induction wire ① Main steps: keep the magnetic field constant, let the conductor ab cut the magnetic induction wire at different speeds, and observe the deflection amplitude of the ammeter pointer. (2) If the deflection amplitude of ammeter pointer is the same, it means that the magnitude of induced current has nothing to do with the moving speed of conductor cutting magnetic induction line; If the deflection amplitude of ammeter pointer is different, it shows that the magnitude of induced current is related to the moving speed of conductor cutting magnetic induction line. Other reasonable answers are also given. 5. Comprehensive application questions 1, (1) E 1