Physics examination questions of grade three

Physics examination questions of grade three

1. Multiple choice questions: (2 points for each blank, ***36 points)

1. Generally speaking, the voice of male students is always deeper and deeper than that of female students, that is, the tone is generally lower than that of female students. The reason is that the vocal cord vibration frequency of boys is higher than that of girls ()

A. lower B. higher C. same D. higher and lower

2. The thunder came and the lightning flashed away, but the thunder kept rumbling. This is because ()

A. thunder breaks out one after another B lightning is formed by repeated reflections from the ground, mountains and clouds.

C. Binaural effect D. Lightning travels faster than thunder.

3. Fill a glass with different amounts of water in turn, and tap it gently with a thin stick to hear different frequencies. Similarly, when a doctor checks whether there is water in a patient's abdomen, he often pats the patient's abdomen with his hand and listens carefully to the sound it makes. This is called "refusing to diagnose". What is the main basis for doctors to judge whether there is hydrops in the abdominal cavity of patients? ()

A. The tone of the sound B. Loudness C. Timbre D. Is the sound pleasant?

Fishermen living by the sea often see such a scene: the wind is sunny, the wind is sunny, and there are handfuls of small "parachutes"-jellyfish, which are floating leisurely in the offshore. Suddenly, the jellyfish left the coast and swam to the sea as if they had received some orders. After a while, the wind roared and the waves were rough, and the storm warning died. Only the inclined part is thickened, and the following explanation is reasonable ()

A. jellyfish receive infrasound waves. B. jellyfish receive electromagnetic waves

C. the jellyfish felt the sudden change of temperature.

If your neighbor often sings loudly and interferes with your study or rest, in order to reduce the interference, the following measures are ineffective ().

A. Open the doors and windows to let the air circulate. B. Plug your ears with cotton.

C. hang it on the partition wall with a cotton blanket. D. Ask the neighbors to lower the volume when singing.

6. When Xiao Ming looked at his fingerprint with a magnifying glass, he felt that the image of the fingerprint was too small. In order to make the fingerprint image bigger, the following statement is true ()

A keep your eyes and fingers still, and keep the magnifying glass away from your fingers.

B keep your eyes and fingers still and put the magnifying glass slightly close to your fingers.

C keep the magnifying glass and fingers still, and keep your eyes away from the magnifying glass.

D keep the magnifying glass and fingers still, and keep your eyes slightly close to the magnifying glass.

7. The images we often mention are: ① pinhole imaging; ② Plane mirror imaging; ③ magnifying glass imaging; (4) the image on the movie screen; ⑤ Images in the rearview mirror. Among them ()

A. The image formed by reflection is 25B. The image formed by refraction is 1③.

C. The real image is 123D. Belonging to the virtual image is 234.

8. Among the four phenomena shown in Figure 1, () c. Verify that the image formed by the plane mirror is a virtual image. D. Verify that the imaging of the plane mirror satisfies the law of light reflection.

9. In the experiment of studying the imaging characteristics of flat mirror, you can see the image of the candle behind the glass plate by placing a candle before and after the erected 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.

C The former is an image formed by light refraction, and the latter is an image formed by light reflection.

D The former is an image formed by light reflection, and the latter is an image formed by light refraction.

10. The following description of various meteorological reasons is correct ().

A. Fog is formed by sublimation of ice on the ground.

B the frost on the stone is formed by the exothermic solidification of water droplets.

C. Dewdrops on lotus leaves are formed by exothermic liquefaction of water vapor in the air #

D. snow is formed by evaporation of rainwater.

1 1. In summer, when bottled mineral water is taken out of the refrigerator, it is often found that the outer wall of the bottle is "sweating" because ().

A. Water will slowly seep out of the bottle. B. Water vapor in the air will liquefy when it is cold.

C. The water on the outer wall of the bottle is constantly vaporizing D. The air around the bottle is constantly condensing.

12. [2006] The indoor temperature is 200℃, and cotton soaked in a little alcohol is wrapped on the glass bulb of the thermometer. With the rapid evaporation of alcohol, which picture in Figure 5 correctly reflects the change of thermometer reading with time ()?

13. [2006 Zhenjiang] The following statement: ① The weather is really hot; ② The object absorbs heat; ③ Friction generates heat; (4) the heat is unbearable. Among them, "heat" means "temperature" is ()

A.①② B.①③ C.②③ D.①④

14. [2006 Jilin] What is wrong in the following statement is ()

A. dry ice is used to sublimate and absorb heat in artificial rainfall. B. It often frosts in winter morning, which is a sublimation phenomenon.

C. The reduction of the volume of ice cubes in drinks is a melting phenomenon.

D. Opening the wrapping paper of popsicles in summer will produce "white gas", which is a vaporization phenomenon.

15. The size of the conductor resistance has nothing to do with the following factors is ().

A. conductor length B. cross-sectional area C. conductor material

D. voltage across the conductor

16. At room temperature, the following classification is reasonable ()

A. pencil lead and rubber are conductors. Plastics, dry wood and ceramics are insulators.

C. iron, germanium and silicon are semiconductors. The heating wire and fuse of electric furnace are conductors with high resistance and high melting point.

17. As shown in Figure 5, the power supply voltage is 3V. Close the switch, and the voltage indicates the number.

For 2V, then:

A. the voltage on the bulb L 1 is 2 volts.

The voltage on the bulb L2 is 2V.

The voltage on the bulb L 1 is 3V D, and the voltage on the bulb L2 is1v.

18. In the circuit shown in Figure 7, the voltage U is constant and the switch K changes from closed to open. The following statement is correct.

A. The reading of ammeter increases B. The reading of ammeter decreases C. The reading of voltmeter increases D. The reading of voltmeter decreases.

2. Fill in the blanks (every space 1 minute, *** 16)

1.At 7: 40 on March 7, 2006, the citizens of Daqing, Heilongjiang Province were surprised to find that there were many "little suns" around the rising sun in Ran Ran, Ran Ran, and a beautiful rainbow appeared above the sun. The main reason for this phenomenon is that there are many small ice crystals hanging vertically in the cloud under special weather conditions (small ice crystals are equivalent to prisms).

(1) The rainbow in the sky shows that sunlight is a kind of (fill in "monochromatic light" or "polychromatic light").

(2) People can see many "small suns" because sunlight is reflected and superimposed by small ice crystals to form a virtual image.

2. Bats can find insects through ultrasonic waves, indicating that sound can spread _ _ _ _ _ _ _; Surgeons can use ultrasonic vibration to remove stones in the human body, which shows that sound can spread _ _ _ _ _ _ _.

3. In order to measure the depth of a certain place on the seabed, scientists vertically emit ultrasonic waves to the seabed, and after 4 seconds, they receive echo signals, showing that the depth of the seabed here _ _ _ _ _ _ _ _ _ m (the propagation speed of ultrasonic waves in seawater is 1500m/s).

Nanning, known as "Greentown", planted many trees on both sides of the street. This is a way to reduce noise, thus making our living environment quieter. In order to protect hearing, the noise should be controlled within _ _ dB.

5. The following four examples describe the "high" sound:

This song is too high for me to sing. She sang loudly. She is a soprano. (d) Please don't "speak loudly". Where _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

6. Xiaogang took beautiful pictures at the bottom of the pool filled with water with a well-adjusted camera. After draining the water, Xiao Gang also wants to take clear photos in the original position with this camera. He should adjust the camera to make the lens _ _ _ _ _. (Please fill in "Extend Forward", "Retract Backward" or "Don't Move")

7. Through experiments, we can know that when the convex lens becomes a real image, the dividing point between enlargement and reduction is that the object is located in _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

8. [2006] The temperature of water in the boiling process (choose "increase", "decrease" or "constant") and the process water (choose "endothermic", "exothermic" or "neither endothermic nor exothermic"). At standard atmospheric pressure, the melting point of alcohol is-1 17. The melting point of mercury is -39℃ and the boiling point is 357℃. Do you think _ (choose "alcohol" or "mercury") thermometer should be used to measure the temperature of boiling water? Liquid thermometer uses the characteristics of liquid to measure temperature.

Three. Drawing questions: (No.1 question 2 points, No.2 question 1 point, No.3 question 2 points, * * * 5 points)

1. As shown in the figure, the image of the object AB in the plane mirror MN is formed according to the imaging characteristics of the plane mirror.

2. As shown in the figure, it is the emergent light refracted by the convex lens. Please draw the corresponding incident light in the picture. 3. According to the physical diagram shown in Figure 8, draw the corresponding circuit diagram in the right box.

Verb (abbreviation of verb) Comprehensive application problem: (per case 1 point, * * * 14 point)

1.

The eyes of humans and some animals are like cameras. The lens in the eyeball is equivalent to a convex lens, and the retina is equivalent to a light screen. When we look at an object, we adjust the bending degree of the lens through the expansion and contraction of the ciliary body and change the focal length of the lens, so that objects at different distances can produce clear inverted real images on the retina with the same image distance, as shown in figure 1.

The difference between eyes and cameras is that human eyes get clear images by adjusting the focal length, while ordinary cameras make clear images by changing the image distance.

The farthest point that the eyes can see clearly is called the far point, and the far point of normal eyes is extremely far. The nearest point where the eyes can see clearly is called the near point, which is about 10cm away from the eyes. The distance to look at an object for a long time is called visual distance, and the visual distance of normal eyes is 25cm. The angle between two straight lines drawn from the optical center of the eye to both ends of the object is called the viewing angle. The bigger the angle of view, the bigger the angle of view.

After reading the above, please answer the following questions:

(1) What the human eye sees is the real image of _ _ _ _ _.

(2) The best distance for normal eyes to observe objects is _ _ _ _ _.

(3) Someone has normal eyesight. When he carefully observes his face with a flat mirror, it is most appropriate to take the mirror away from his eyes.

8 .. [2006 Huai 'an] Huibo is crystal and paraffin is amorphous. The melting images of hypo and paraffin collected by Xiaohua through consulting data are shown in the figure, and the melting image of hypo is _ _ _ _ _ (fill in the serial number). The information obtained by analyzing the field is as follows:

①_____________________________

②_____________________________

The information that can be obtained by analyzing image B is _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ (only fill in one item).

1. in the experiment of "measuring the resistance of small bulbs with voltmeter and ammeter"

(1) Add a wire between the power supply and the sliding rheostat in figure 10 to make it a correct measuring circuit;

(2) Table A in Figure 10 should be _ _ _ _ _ _ _ _ _ _ _; Table B should be _ _ _ _ _ _ _ table;

(3) The reading of ammeter in figure 1 1 is _ _ _ _ _ _ _ a; The reading of the voltmeter _ _ _ _ _ _ _ _ _ V；; Therefore, the measured resistance is _ _ _ _ _ _ Ω.