Question

Hi, I really need help. I was on a homework help site for 140 minutes, and as soon as it was my turn, it logged me out. I need help with Ohm's Law, I understand nothing. I am in grade nine. Please help me. First of all, what is Ohm's Law? (Science, Physics)

Answer 1

I'm not that great at physics or electrical engineering

but according to this page
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmlaw.html


Ohms law is

I = V/R

I = current
V = voltage
R = resistance

Answer 2

@jim_thompson5910 thanks! I kind of understand that, but my teacher taught us like 10 equations, and I know nothing and I have a unit test tomorrow. Thanks for looking that up though

Answer 3

which 10 equations are you supposed to know?

basically equations like that?

Answer 4

I really don't know. we did some equations involving circuits, and then we did some about phantom load. like when the tv is plugged in for 3 weeks, how much energy is used

Answer 5

Jim already explained it...Ohm’s law is electric current=voltage/resistance

Answer 6

What part you don't understand

Answer 7

I understand that, but my teacher taught us a bunch of different equations related to it

Answer 8

i will find one of my questions and post it just a sec

Answer 9

\(\large\Omega=\frac{V}{A}\) is also one :D

Answer 10

Look at this website...it may help you

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmlaw.html

Answer 11

Anyway, I'll wait for the question to be posted

Answer 12

Thanks for adding that thomaster

Answer 13

@blast234 thanks!
I am kind of dumb when it comes to physics...so whats a conducter

Answer 14

just finding it one sec

Answer 15

something that allows electricity or electric charge to flow through it

contrast that with an insulator which does not let charge flow through

Answer 16

a conductor conducts electricty

Answer 17

I know all of the equations

Answer 18

Conductors are materials that permit electrons to flow freely from atom to atom and molecule to molecule.

Answer 19

oh my goodness. i cant stand physics. there are so many things i dont know. like... percent efficiency... Eout over Ein x100%

Answer 20

ok... i tthink i get that. like in a light bulb. how much energy goes in, how much comes out and the percent is the waste... or the perecent that actually comes out?

Answer 21

that's like saying if you put in 20 units of effort into the system and get 10 units of effort back out, then you're getting

(Eout)/(Ein)*100 = (10/20)*100 = (1/2)*100 = 0.5*100 = 50% efficiency

Answer 22

so yeah, it helps you see how much is being wasted, in this case 50% is wasted

Answer 23

Efficiency is measured by Work out/Energy in . Heat is not work. Work + heat always amounts to 100% of the energy.

Answer 24

what is E=Pxt

Answer 25

and C= ExR???

Answer 26

IM GUESSING THIS HAS NOTHING TO DO WITH OHM'S LAW ,,,

Answer 27

Energy = Power x Time. is E=Pxt

Answer 28

2. A microwave was used 5 hours a day for 7 days. This power required for this microwave is 2.5 kW. Cost much would it cost to run the microwave for 1 week. The rate for the usage of electricity is $0.07 kWh (4pts)

Answer 29

this is Eout over Ein x100% right?

Answer 30

no you just do a bunch of conversions really

5 hours/day * 7 days = 35 hours total

35 hrs * 2.5 kW = 87.5 kWhours

(87.5 kWhours)*(0.07 dollars/1kWhour) = 6.125 = 6.13 dollars

Answer 31

so would this be,,,
5x2.5kW= 12.5kW
12.5 kWx7 = 87.5kWh

87.5x the cost???

Answer 32

Oh thanks!!

Answer 33

yeah it uses up 87.5 kW total (over 35 hours), you then use that to find the total cost

Answer 34

how do i convert the watts? because i remember my teacher saying something about kilowatts, mega watts and other stuff

Answer 35

1000 watts = 1 kilowatt

Answer 36

are u guys in the same grade or in a higher grade than me?

Answer 37

oh right right! i need to remember that!

Answer 38

1,000,000 watts = 1 megawatt

Answer 39

hopefully she'll put that in the test for our class to remember

Answer 40

Explain the difference between how a non renewable recourse can create electricity vs a renewable resource.

Answer 41

what is this?

Answer 42

just remember the prefixes and you'll be fine

kilo - thousand
watt - watt

so

kilo + watt = thousand watts

Answer 43

what is a watt? the unit to measure electricity?

Answer 44

it's a measure of energy consumption I think

Answer 45

i really hope ur in a higher grade than me... or else i'll be very sad lol

Answer 46

ok...thanks

Answer 47

oh to be more precise, it's a unit of power where

power = energy/time

Answer 48

thanks so much this really means alot

Answer 49

np

Answer 50

r u in a higher grade than me?

Answer 51

tbh, you're better off asking this in either the science, physics, computer science sections since this really isn't math

you'll find better experts in there

Answer 52

yes

Answer 53

wait what? omg. i havnt been on here since january, and i never logged out. i guess i was in a big rush, and i never checked!!!

Answer 54

do u have instragram. u dont have to reply if u dont want to lol im not tryna be a stalker

Answer 55

no have never used the service

Answer 56

and yes you should check out the other sections to see if they have what you're looking for

Answer 57

oh ok.
thanks a lot!!!1

Answer 58

thanks u so much! bye now!

Answer 59

yw, good luck

Answer 60

@jim_thompson5910 thanks im going to need it. the unit test is tomorrow and i crammed. hopefully, though, i'll do beeter on the final exam mid june. im going to start styding now

Answer 61

do you use a graphing calculator?
If you do you can use a program where you can insert all the formulas.
I did this for my physics test a few years ago the teachers even recomended it.
It takes away much stress if you don't have to remember a thousand formulas which you aren't going to remember after the test anyway.