Conversion Question

Discussion in 'Homework Help' started by ElectronicsFanatic, May 6, 2012.

  1. ElectronicsFanatic

    ElectronicsFanatic Thread Starter Member

    Joined:
    Feb 12, 2012
    30
    1
    For some reason I have really confused myself on how to do these homework assignments that are asking me to complete the conversions.

    Here is one:
    0.0001 MHz = ______Hz
    What is throwing me off is that it is saying .0001Mkz. I am thinking that i would need to reduce this number to make it smaller since Hz is smaller than MHz so I am coming up with this number:
    .1 x 10^-9

    Am I doing this right? I don't get the feeling that I am doing this right? Could you send some hints my way?
     
    #1
  2. bertus

    bertus Administrator

    Joined:
    Apr 5, 2008
    13,995
    1,774
    #2
    ElectronicsFanatic likes this.
  3. ElectronicsFanatic

    ElectronicsFanatic Thread Starter Member

    Joined:
    Feb 12, 2012
    30
    1
    Ok I have looked at the metric system prefixes and what is confusing me so much is the fact that it says 0.0001Mhz. I haven't had to deal with decimals like this before. When it says Mhz I think 1,000,000. But the way that my brain is telling me is that this is supposed to be 100μHz but it is in Mhz with μHz notation.

    So if i follow the chart you provided i would need to get rid of 6 decimal places to make it 100Hz?
     
    #3
  4. bertus

    bertus Administrator

    Joined:
    Apr 5, 2008
    13,995
    1,774
    Hello,

    Yes, 100 Hz is the correct answer.

    Bertus
     
    #4
  5. ElectronicsFanatic

    ElectronicsFanatic Thread Starter Member

    Joined:
    Feb 12, 2012
    30
    1
    Ok, Thanks for the help. I know this is pretty easy, but I got myself all mixed up somehow and needed a push in the right direction again.
     
    #5
  6. MrChips

    MrChips Moderator

    Joined:
    Oct 2, 2009
    11,758
    3,010
    Use 1M = 10^6

    0.0001 = 10^{-4}

    Hence 0.0001M = 10^{(-4  +  6)} = 10^2 = 100
     
    Last edited: May 6, 2012
    #6
  7. WBahn

    WBahn Moderator

    Joined:
    Mar 31, 2012
    12,823
    3,230
    Here is one place where using the units can really help out. Here is one way to approach it:

    <br />
x Hz = 0.0001 MHz<br />

    Your goal is to find the value of 'x' that makes this expression true and you will accomplish by multiplying the right hand side by values of 1 (so the value is not changed) but choosing how you express the value of 1 such that the units do change.

    <br />
x Hz = 0.0001 MHz \ \times \ \frac{10^6 Hz}{1MHz}<br />

    Here we have just multiplied the right hand side by 1, since the numerator (10^6Hz) is equal to the denominator (1MHz).

    <br />
x Hz = (0.0001)(10^6) Hz \ \times \ \frac{1MHz}{1MHz}<br />

    Here we have just rearranged factors, nothing more.

    <br />
x Hz = 100 Hz<br />

    Here we have merely carried out the math and removed factors that cancel.

    Another way to approach it is to treat the prefix as what it is, a multiplier separate from what it is multiplying:

    <br />
x Hz = 0.0001 MHz<br />
x Hz = (0.0001)(M)(Hz)<br />
x Hz = (0.0001)(M)(Hz) \times \frac{10^6}{M}<br />
x Hz = \frac{(0.0001)(M)(Hz)(10^6)}{M}<br />
x Hz = (0.0001)(10^6)(Hz)<br />
x Hz = 100 Hz<br />
     
    #7
Loading...