V/r = I

reallylongnickname · 2012-05-26 04:46:02

I don't get why the answer isn't 20KA. 20 divided by 1 is 20. The answer hasn't been converted down to milli amps yet.

My method is this: Divide the numbers first, then move the decimal three steps to the right in order to convert to milli amps. What rule am I not following in mathematics?

Last edited by reallylongnickname (2012-05-26 04:52:08)

bobbym · 2012-05-26 04:50:21

Hi;

Isn't that a 1000 ohm resistor?

reallylongnickname · 2012-05-26 04:56:02

Sorry, I added this to the original post before your reply:
My method is this: Divide the numbers first, then move the decimal three steps to the right in order to convert to milli amps. What rule am I not following in mathematics?

Yes 1000 ohms resistor or 1K.

bobbym · 2012-05-26 04:59:48

Yes 1000 ohms resistor or 1K.

I wasn't really asking that question. I was trying to get you to remember the units that ohms law works in.

20 / 1000 = .02 A

.02 amps is 20 milliamps

decimal three steps to the right in order to convert to milli amps

Moving the decimal 3 digits to the right is multiplication by 1000. Here you are dividing by 1000.

reallylongnickname · 2012-05-26 05:30:51

If I use the full method, I get the correct answer but this seems long process.

Last edited by reallylongnickname (2012-05-26 05:43:43)

bobbym · 2012-05-26 05:38:23

Hi;

The latex is not coming out correctly.

Did you read post #4?

reallylongnickname · 2012-05-26 05:44:29

Last edited by reallylongnickname (2012-05-26 05:46:21)

bobbym · 2012-05-26 05:53:13

Hi reallylongnickname;

That is not right.

If you are going to use scientific notation there is 10^3 on the bottom not a 10^(-3). And no 20.

reallylongnickname · 2012-05-26 06:07:31

bobbym · 2012-05-26 06:09:18

Sorry the top is fine.

20 x 10^3 = 20 x 1000 = 20000 so the bottom is incorrect.

Bob · 2012-05-26 06:09:21

hi reallylongnickname

Let's just take a step back and re-visit Ohm's law.

1 ohm is defined as the resistance that delivers 1 amp when the voltage is 1 volt.

So if you have 20 volts and 1 ohm then the current will be 20 amps.

If you increase the resistance the current will go down.

So if you have 20 volts and 1000 ohms the current is

If you want to write the numbers in standard form (and you really don't need to) then its:

Hope that helps

Bob

reallylongnickname · 2012-05-26 06:13:06

ok thx I get it

Last edited by reallylongnickname (2012-05-26 06:15:23)

bobbym · 2012-05-26 07:03:09

Hi reallylongnickname;

Try to think about these quantities as a hobbyist would.

A neat analogy to help understand these terms is a system of plumbing pipes. The voltage is equivalent to the water pressure, the current is equivalent to the flow rate, and the resistance is like the pipe size.

http://science.howstuffworks.com/enviro … ion501.htm

Math Is Fun Forum

#1 2012-05-26 04:46:02

V/r = I

#2 2012-05-26 04:50:21

Re: V/r = I

#3 2012-05-26 04:56:02

Re: V/r = I

#4 2012-05-26 04:59:48

Re: V/r = I

#5 2012-05-26 05:30:51

Re: V/r = I

#6 2012-05-26 05:38:23

Re: V/r = I

#7 2012-05-26 05:44:29

Re: V/r = I

#8 2012-05-26 05:53:13

Re: V/r = I

#9 2012-05-26 06:07:31

Re: V/r = I

#10 2012-05-26 06:09:18

Re: V/r = I

#11 2012-05-26 06:09:21

Re: V/r = I

#12 2012-05-26 06:13:06

Re: V/r = I

#13 2012-05-26 07:03:09

Re: V/r = I

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