Recent content by chris_yau

  1. C

    Magnetic fields around electric current

    Thank you for your help~!
  2. C

    Magnetic fields around electric current

    To be frank, it is the question in the report. Actually, I didn't see the increase of the sensitivity. The amplitude is steady.
  3. C

    Magnetic fields around electric current

    I have just done an experiment of magnetic fields around electric current in straight wire by using the seach coil. I have 2 questions about this... (1)why is this necessary to ensure the search coil is at the same level as the wire? My anwser:If the seach coil is not at the same level as...
  4. C

    Testing Iron Ions in Oxygen Absorbers

    If we add dil. HCl to dissolve the oxygen absorber and then add NaOH. Green ppt. will ba formed if there are iron(II) ion and brown ppt. for iron(III) ion. However, if the oxygen absorber contains both iron(II)and iron(III) ion, how can we test it??
  5. C

    Testing Iron Ions in Oxygen Absorbers

    how to test the component inside oxygen absorber in food?? we guess that there may be iron(II) or iron(III) ion. we use reducing agent or oxidzing agent to test it ? however, if both of them exist in the oxygen absorber, how can we distinguish them?? :confused:
  6. C

    Phase difference in CR and LR circuits

    I have thought about this today. (1) The channel 2 will be earthed if channel 1 is only connected the capacitor. Thus, we cannot observe the trace 2 and cannot compare the phase difference. (2) There is no phase difference between trace 2 and the current since this is the voltage across the...
  7. C

    Phase difference in CR and LR circuits

    I have just done an experiment on CR and LR circuits. http://img9.picsplace.to/img9/21/RC.jpg Connect channel 1 of the CRO across both the capacitor and resistor and channel 2 across the resistor.The trace on channel 1 is taken as the p.d. across the capacitor and that on channel 2 as ths...
Back
Top