# 17.1 Maple Help

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kibakun
Guest

## Questions 1, 2, 3 , 4

1. I = q/t
Conventional direction of the current runs opposite to electrons

2. V = R * I
In the direction of conventional the voltage drops

3. Vab = Ir

Terminal is always less than nominal

4. R = p * L/A or p = RA / L

kibakun
Guest

## Re: 17.1 Maple Help

how do you convert mA to A?

helpplss
Guest

## Re: 17.1 Maple Help

to convert mA to A divide by 1000

guest_01
Guest

## Re: 17.1 Maple Help

A 231.1 mA current flows through a 2.04 k resistor.

im put the mA into A's but why does it say 2.04 k ? do you have to do something with that or you just multiplying? its not working for me

excuze m
Guest

## Re: 17.1 Maple Help

you dont have to convert k it doesnt mean anything... for 2 and 3 one of them you have to convert from mA and the other you don't have to... just play around with it alittle.

kibakun
Guest

## Re: 17.1 Maple Help

I'd just like to give what I believe is a helpful tip, especially for questions like Question 2.

Besides remembering Ohm's Law as V=IR (this way I pronounce it out: Vurr ), there's a handy little chart to remember the equation and help you find what you are looking for.

When you need to find the part you are looking for, just cover the letter and read out the new equation.

For instance to find Voltage V. Block out the V and you have the equation to figure it out which is now I*R

Same goes for the current I just place your finger over the I in the chart and you then have V/R

There are also a few for calculating with Power and Energy, if it's ever needed.
The formula for Energy being the same as for Voltage E=I*R. Power is P=I2*R.

Hope that helps!

Guest01

Posts : 133
Join date : 2008-09-19

## 17.1 #4

can somebody post a detailed way to do number 4 i just can't seem to get it
thanks!

frustrat
Guest

## Re: 17.1 Maple Help

yo i still cant get #2 for some reason. I took my mA and divided by 1000 which made it a decimal. Then i did my resistance/amps and i get another decimal but its still not working. what am i doing wrong?

Guest

## #2

i'm not getting this either, i converted the mA to A by dividing by 100 then multiplied that with given kI. (tried converting kI to I as well by either multiplying by 1000 or dividing by)

i know the answer is negative though

:)
Guest

## #4

for number 4:

A 356.8 mA current flows through a 52.89 cm long wire with a 0.5 V potential difference across it. The wire is cylindrically shaped and has a radius of with 0.827 mm. What is the resistivity of the wire material (see sheet 13,16) ? Indicate with a positive (negative) sign whether the resistivity depends (does not depend) on the cross sectional shape of the wire.

use p=RA/L
p= resistivity of material
R= resistance
A= area
L= length

R=V/I so .5V/.3568A = 1.40135 ohm
A=pi*r^2 = pi(.000827^2)= 2.149*10^-6

then just plug everything in:
p=RA/L
p= (1.40135(2.149*10^-6))/.5289
p=-5.69389*10^6

guest768
Guest

## Re: 17.1 Maple Help

can someone please further explain question 2 and 3!!!

guest1
Guest

## Q2 and Q3

I am also having trouble with Q2 and Q3 plz help?

sjames
Guest

## #2&3

V=R*I
R=4.212
I=221.4mA
answer is neg 932.537 do not convert
I just got #3
r=(E-V_ab)/I
E=2.9
V_ab=1.817
I=197.7/1000
So....r=(2.9-1.87)/.1977
hope this helps
PS One BIG fat raspberry for the joke about using this site is considered cheating

super mo
Guest

## Re: 17.1 Maple Help

why dont you convert?

hmmm
Guest

## Re: 17.1 Maple Help

I am not sure. I gotta go to a class good luck!

super mo
Guest

## Re: 17.1 Maple Help

so basically for question 3

subtract the two voltages given and divide it by the current thats given that u converted (meaning mA to A by dividing by 1000)

guest1
Guest

## questions

Dude at least try the questions before you come to the blog for help. Some of these are so easy it takes like 5 min to work around.

kibakun
Guest

## Question 1

A current of 2.601 A flows through a conducting wire. How much charge passes through it in 3.151 hours (see sheet 2,4,14) ? Indicate with a positive (negative) sign whether the coventional direction of the current is in the (opposite to the) direction of the moving electrons.

How do i do this? i know it maybe easy for most people, but i can't seem to understand it. I tried using the equation and no good. I also looked at the cd and i am still not getting it. You have to convert hours to seconds right?

Guest911
Guest

## 1

I AM STILL NOT GETTING #1, PLZ HELP

maria
Guest

## #1

can someone help us with #1

#1
Guest

## Re: 17.1 Maple Help

#1 is simply a rearrangement of the formula I = q/t to get q, make sure you convert hours to seconds.

Does anyone know why we convert the mA to A in #3 but not #2???

J
Guest

## Question 1

for question 1 what i did was i took my 2.101 A divided that by 3.151 hours well i converted to seconds....so it came to be 11343.6 seconds...so i did 2.101/11343.6 and it gives me the wrong answer still

Guest091
Guest

## Re: 17.1 Maple Help

miliamperes (mA) is just a thousandth of an ampere (A). This is no different then describing the relationship between milimeters and meters. Same shit as last semester.

To convert mA into A divide mA by 1000 (or multiply by 0.001).

You will need to convert your Ohms as well, from kiliohms to ohms. These conversions will bring everything to S.I. Units.
Simple stuff, I hope this will be the last explanation of it.

For Question 1 you will need to convert hours into seconds. Multiply hours and 3600 (that is 60*60 - converting hours into minutes; the first 60, then minutes into seconds; the second 60)

Again shit we have done in the past fall.

Rearrange the equation to suit your needs.

Guest01

Posts : 133
Join date : 2008-09-19

## Guest01

I don't know if this is a mis communication or if you are indeed being an asshole. It may seem super easy for you to see some of these things, but there are students in this class believe it or not, that are still trying to understand this stuff. Yes you will have lazy students here and there, but there are students who really don't understand number 2/1. So if you think students asking questions is annoying then dont freaking use the site. Otherwise stop being an asshole explaining the answers like you were some self righteous ass.

play nic
Guest