Solving Ohm's Law Homework Questions

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Homework Help Overview

The discussion revolves around applying Ohm's Law to a series of problems involving electrical circuits, specifically focusing on calculating current, voltage, and resistance in various scenarios. Participants are working through questions related to a battery-powered curling iron, a strobe light, a CD player, an electrical pump, and a lamp connected to a wall outlet.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • Participants express confusion about how to start solving the problems and seek clarification on the application of Ohm's Law. Some suggest using the formula V = I x R, while others question the understanding of the law itself. There are attempts to break down the problems into simpler components, but uncertainty remains about the calculations and the relationships between voltage, current, and resistance.

Discussion Status

Some participants have made progress on the first two questions, calculating current using the provided values. However, there is a lack of consensus on how to approach the remaining questions, with some expressing frustration and confusion about the underlying concepts. Guidance has been offered regarding the use of Ohm's Law, but clarity on its application is still being sought.

Contextual Notes

Participants mention feeling lost and confused about the principles of Ohm's Law and its mathematical representation. There is an indication that some may not have a strong foundation in algebra, which is impacting their ability to solve the problems effectively.

WMM
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Homework Statement


1. A nine volt battery supplies power to a cordless curling iron with a resistance of 18 ohms. How much current is flowing through the curling iron?
2. A 110 volt wall outlet supplies power to a strobe light with a resistance of 2200 ohms. How much current is flowing through the strobe light?
3. A CD player with a resistance of 40 ohms has a current of 0.1 amps flowing through it. Calculate how many volts supply the CD player?
4. A small electrical pump is labeled with a rating of 3 amps and a resistance of 40 ohms. What voltage was it meant to run at?
5. A lamp is plugged into the wall outlet, which is providing 110 volts. An ammeter attached to the lamp shows 2 amps flowing through the circuit. How many ohms of resistance is the lamp providing?

The Attempt at a Solution

Don't know where to start.
 
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Start with question 1 and apply Ohm's Law as the title of your post suggests.
 
As you stated in the title, Ohm's Law. Simply plug what you know into Ohm's Law and solve for the unknown value.
 
p21bass said:
As you stated in the title, Ohm's Law. Simply plug what you know into Ohm's Law and solve for the unknown value.

I'm lot though I know about it but they tell you what Ohms law is and it confuses me.

f9ae53a99f2b2b6a74146fb04fb3ff73.png
 
WMM said:
I'm lot though I know about it but they tell you what Ohms law is and it confuses me.

f9ae53a99f2b2b6a74146fb04fb3ff73.png
What confuses you? Can you state in plain English and without equations what Ohm's Law says?
 
What do I use to figure out the problem?
The only thing it gives me is 18ohms for the first one.

Just completely lost and when I try to read about the Ohms law none of it makes sense.
 
Does V = I R make more sense? Some times Ohm's Law is written in this form.
 
it is very simple..

the current equals the voltage divided by the resistance...
and in first problem, the voltage equals 9 V (9V battery) and the resistance is 18 ohms...

so try to figure it out...
 
So the current is 2? What is that measured in, AMPS?
 
  • #10
WMM said:
So the current is 2? What is that measured in, AMPS?
Look it up.
 
  • #11
no... voltage divided by the resistance = 9 / 18 = 1/2...

and yes, current is measured in amps
 
  • #12
1. Since V and R are known, solve for I which is current by dividing both sides of the equation by R.

V = I x R
R R

I = V
R

I = 9
18

I = 0.5 Amps

2. Current = 0.05 Amps

I managed to get the first 2 done.

No I'm stuck on the last 3.
 
  • #13
uhh...it doesn't seem like you are even trying.. doesn't physics require you to have some knowledge of algebra at least...?

you already have the equation right there: V = I x R
all the problems give you 2 of the unknown variables.. why can't you solve for the one remaining variable?
 

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