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Everything posted by Primarygun

  1. V1/V2=N1/N2 This can be applied only when the magnetic flux does not pass to other objects except the 2nd coil?
  2. Yes, air core transformer exists. Generally, air-core transformers are used when the voltage source has a high frequency (above 20 kHz). Iron-core transformers are usually used when the source frequency is low (below 20 kHz I've got a look at it,but I still can't figure out the answer. Is it all the P=[power given out by the primary transformer minus power loss by the main three ways]must be absorbed in the secondary circuit whatever the load is?
  3. Primarygun


    What happens to the energy loss if the iron core in a transformer is taken out? I think the energy loss will reduce, is it right?
  4. Where will bromine be observed in an organic solvent? Varies with different organic solvent with various density? And what kinds of common organic solvent are toxic?
  5. I agree with you as I don't think I'd use the back-up thing provided for every single file
  6. Ryan, I think it's easy to explain but difficult to predict, isn't it?
  7. As my new set of computer is recently bought from Dell, my DVD player supports both formats. The shopkeeper persuaded me to buy -R when I enquiried about the things,i.e. the first question I asked here. He told me that +R cannot be recognised by some DVD players without any elaboration and +R is traditionally used for burning data while -R is prefered to movie( also data) When I ask why politely, he said he'd already told me.
  8. Generally, I burn data into my disc. Last time, after my DVD was entered a total sum of 750 MB files, I couldn't burn any more into it, leaving 3.6G space unused.
  9. I've recently bought a DVD burner and several DVDs, but I am a beginner of this kind of thing. 1.What's the difference between +r and -r? 2.I can burn DVDR once only which is unlike CDR? 3.What's DLA? my computer alerts me that it is forbidden when I try to burn something. 4.Why do I need to enter a code? I'm afraid I'll make things mess as there only 5 chances. I like watching Western movies, what should I choose? Thanks
  10. What is a chip resetter? A hardware?
  11. Does the difficulty of cracking it increase with price? or vice versa? Have to make a plan for future
  12. I've waited for 12 hours, ok I will wait for another 24 hours.
  13. Yes, I think this is for my case. I found that even if I filled to 3/4 of the cartridge, the printhead tips no ink. My printer is hp psc 1210 all-in-one. I bought it in a shop after telling the shopkeeper what my printer is. The machines can still recognise the printer, so I don't think my oil really stops it working.
  14. I've refilled some ink into my cartridge, but my printer still print out white sheets. I guess the computer cannot recognise the change, how can I solve this problem>?
  15. Oh maybe I should consider it more deeply . Now my concept: You have to overcome te voltage 1.5V "lost" of a used cell. Current is determined by the potential difference, and by P=VI, exactly current is affecting the power delivering back into the cell. So amphere-hour or energy both can be used to find out the time.
  16. What will the reading be if I pass ultrasonic wave towards a metal wall, where I put a CRO beside the transmitter? A linear equation with a negative slope or y=k with several crests?
  17. How are rechargable battery recharged again? Which physical quantities should I consider to estimate the time needed to make the battery full again? The electricity capacity (ampere-hour) or the energy delivered to the battery.
  18. You have to figure out the idea at large first. You should figure out what's in water then Water molecules. Then, why can't we use this method. The general idea is that the gas could not come out again, or could not come out purely. Choose either one. Then, predict what happens exactly when the two molecules mix with each other. That is, hydrogen chloride reacts with water to form hydrochloric acid or it ionizes in water to form acid readily.
  19. Why yeasts are preferred to pumping gases for making bread?
  20. I wonder how long it takes you to finish a copy of Scientific American?
  21. Appreciate all first. Swansont, in my mind, I guess a current will appear in the case of vacuum. Do you agree? The particles carry charge, so they move the oppositely charged plates. Can you tell me about the change in energy of the particles? In my thought, I think the path completed by alpha particles should be of a low resistance, since they are charged. Their energy content cannot be dropped to zero, I think, as their charges couldn't be neutralized unless they reach the plates. If I am wrong with a particular statement, please notify me. Thanks
  22. It normally lasts for 28 days. Does ovulation really occur at the middle of the menstrual cycle or just 14 before the end of a menstrual cycle? Which is more persuasive?
  23. Primarygun


    Imagine that there's a complete circuit except the front is left open, so it is an open circuit. The two ends of the wire are metal plates, similar to electrolytic cell. There's a 2200V voltage connecting in series, just like a battery conecting in series. There's a steam of alpha particle shot to flow perpendicular to the plane in VACUUM. Is there any current generated? What about using beta particles (a) in air (b) in vacuum?
  24. When does menstruation occur in a menstrual cycle which lasts for 22 days? 14 days after the previous one, or at the middle. Thanks
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