20 18 Answers Sharing of National Science Literacy Online Competition
1. Which of the following metals has the strongest conductivity at room temperature?
A. Copper (silver)
C. Gold D. Iron
2. What is the frequency of ultrasound?
A. 20 Hz b. 1000 Hz
C. 15000HZ？ (d) greater than 20000 Hz)
3. Which of the following media spreads sound fastest?
A. Liquid B. Gas
Amorphous solid? Sound propagation does not need media.
4. What is the unit of ship speed?
A. Mach (m)
[C. Section (kn) D. bit (bit)
5. Which of the following foods can be preferred to supplement vitamin A from food?
[A. Rice B. Millet porridge
C. White flour steamed bread D. Lean meat
6. Blood vessels from the heart are called.
A. Veins [B. Arteries
C. Heart beat D. Neither.
7. What will happen to the raw salt in the air?
A. Dissolution B. Weathering
C. crystallization? [D. deliquescence
8. Why should the filament in the light bulb be made of tungsten?
Tungsten has a high melting point. B.tungsten wire looks more beautiful.
C. tungsten has a high hardness. Tungsten has a high density.
9. Who is the inventor of the battery?
Amplifier? [B. Volts
C. Walter Maxwell
10, will electromagnetic radiation cause pollution, and what is it related to?
[A. radiation intensity? B. radiation source
C. Radiation type D. Radiation direction
1 1, which line should the power switch be installed on?
On the line of fire, on the zero line
C. Ground wire D. On the antenna
12. What are the main symptoms of iodine deficiency in children?
A. Palpitation and shortness of breath B. Dyspepsia
[C. mental retardation? D. bradykinesia
65438 March, September and October What did the salmon swim against the current to Heilongjiang?
A. predation? [B. Laying eggs
C. Go back to the warm current
14. What is the name of the third-generation nuclear power brand independently innovated by China?
[A. Hualong No.1? B. Hualong No.2
C.hualong iii d.hualong IV
15. What is the scientific name of cockroach?
A. Dung beetle B. Mayfly
[C. cockroaches? D. chunxiang
16. When is the best time to take antihypertensive drugs?
A.65438+ 0~2 hours after peak blood pressure
[B. 65438+ 0~2 hours before blood pressure peak.
C. not special, at any time
D.late at night
17, what is the largest organ in the human body?
A. kidneys? [B. Skin
C. liver and intestine
18. Who is the ant in charge of finding food?
A. Male ants [B. Worker ants
C. soldier ant D. queen ant
19, the temperature of dry ice will generally reach?
A. MINUS 27 degrees Celsius
-78.5 degrees Celsius -65438 degrees +08.5 degrees Celsius
20. Which of the following statements is correct about wisdom and delay in Close Up?
[A] As a unit of length, a ruler is longer than a straight one.
B. as a unit of length, the branch is longer than the ruler.
As a unit of length, straight is as long as a ruler.
D. Branches and rulers are units of weight.