Finding current problem, where did i mess up?

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In summary, a conducting rod of length 10 cm is pulled along horizontal, frictionless rails at a constant velocity of 7.7 m/s. The rails are connected to a metal strip and a uniform magnetic field of 1.9 T is present, directed out of the page. When asked about the magnitude and direction of the emf induced in the rod, the correct answer is 1.463, taking up to be positive. However, when asked about the magnitude and direction of the current in the conducting loop, assuming a resistance of 0.40 ohms for the rod and negligible resistance for the rails and metal strip, the answer is -3.6575 due to the clockwise motion of positive charges being pushed upward
  • #1
mr_coffee
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The conducting rod shown in Figure 30-52 has a length L and is being pulled along horizontal, frictionless, conducting rails at a constant velocity v. The rails are connected at one end with a metal strip. A uniform magnetic field B, directed out of the page, fills the region in which the rod moves. Assume that L = 10 cm, v = 7.7 m/s, and B = 1.9 T.
Here is the picture:
http://www.webassign.net/hrw/hrw7_30-52.gif

(a) What is the magnitude and direction of the emf induced in the rod? (Take up to be positive.)
I got: 1.463 which was correct.

(b)What is the magnitude and direction of the current in the conducting loop? (Take counterclockwise to be positive.) Assume that the resistance of the rod is 0.40 OHMS and that the resistance of the rails and metal strip is negligibly small.
I used

EMF - IR = 0;
I = EMF/R;
I = 1.463/.40 = 3.6575 which was wrong, any ideas were i messed up? Thanks.
 
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  • #2
The positive charges in the rod, moving to left, are pushed UPWARD
(by the right-hand-rule, okay?), which is in the CLOCKWISE sense.
If COUNTER-clockwise is called positive, your current will be negative.
 
  • #3
Ahh thank you lightgrav!
 

Related to Finding current problem, where did i mess up?

1. Where do I start when trying to find the current problem?

The first step in finding the current problem is to thoroughly review your research or experiment. Look for any inconsistencies or errors in your methods or data collection. It may also be helpful to consult with colleagues or mentors for their insights.

2. How can I determine where I went wrong?

Carefully analyze your data and results to identify any patterns or discrepancies. It may also be helpful to retrace your steps and repeat the experiment or research to see if you get similar results. Additionally, seeking outside perspectives can provide valuable insights into where you may have made a mistake.

3. Is it possible to have more than one mistake that led to the current problem?

Yes, it is possible to have multiple mistakes that contributed to the current problem. This is why it is important to thoroughly review all aspects of your research or experiment to identify any potential errors.

4. How can I prevent making the same mistake in the future?

Documenting your methods and data collection process can help prevent making the same mistake in the future. It is also important to carefully review your work and seek feedback from others before finalizing your research or experiment.

5. Is it possible to fix the current problem or do I need to start over?

It depends on the severity of the mistake and the impact it has on your research or experiment. If the mistake is minor and can be corrected, it is possible to fix the current problem without starting over. However, if the mistake significantly affects your results, it may be necessary to start over to ensure accurate and reliable data.

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