Calculating potential difference

[sallyishyper]

I have done 1, i can't get the right answer for question 2. i seem to be getting minus7.5 volts. i know that's not anywhere near right because you can't get a minus voltage. i have tried many different ways to do this and i still can't get the right answer

To get question 1 i used ohms law which gave me the two answers shown in the attachment, for question 2 i tried using the same method, but that gave me the wrong answer so i tried finding the conductance and from the resistance and the current, but that gave me - 7.5 volts. i ma very confused an i think i might be missing something very simple

https://www.physicsforums.com/attachments/16093

 

[alphysicist]

Hi sallyishyper,

I have done 1, i can't get the right answer for question 2. i seem to be getting minus7.5 volts. i know that's not anywhere near right because you can't get a minus voltage. i have tried many different ways to do this and i still can't get the right answer

To get question 1 i used ohms law which gave me the two answers shown in the attachment, for question 2 i tried using the same method, but that gave me the wrong answer so i tried finding the conductance and from the resistance and the current, but that gave me - 7.5 volts. i ma very confused an i think i might be missing something very simple

https://www.physicsforums.com/attachments/16093

Your attachment does not seem to be there.

 

[tmusgrove]

I couldn't get the attachment either, says that there is an error.

 

[tiny-tim]

Hi sallyishyper!

Can you give us the url of your picture?

 

[rdl]

/Hello,

Thank you for sharing your concerns about calculating potential difference. It sounds like you have put in a lot of effort but are still having trouble getting the correct answer for question 2. First of all, I want to reassure you that it is completely normal to struggle with certain concepts or calculations in science. It takes practice and sometimes trial and error to fully understand and master a concept.

Now, let's take a closer look at the issue you are facing. You mentioned using Ohm's Law to calculate potential difference in question 1, which is a valid approach. However, it's important to make sure that all of your units are consistent when using this formula. For example, if you are using resistance in ohms, then your current should be in amperes and your potential difference will be in volts. Double check to make sure you are using the correct units in your calculations.

For question 2, it seems like you have tried different methods but are still getting a negative value for potential difference. This could mean that there is an error in your calculation or that you are missing some key information. Without seeing the specific problem, it's difficult for me to pinpoint the exact issue. However, I can offer some general advice.

First, make sure you fully understand the concept of potential difference and how it relates to resistance and current. It may help to review some basic principles of electricity and circuits. Additionally, try breaking down the problem into smaller, simpler steps. For example, calculate the resistance and current separately before finding the potential difference. This can help you identify where the mistake is happening.

If you are still having trouble, I suggest reaching out to a classmate, teacher, or tutor for additional help. Sometimes having a different perspective can make all the difference. Don't get discouraged and keep practicing. With persistence and determination, I am confident you will be able to find the correct answer.

Best of luck!