Magnetic field questionwhat did i do wrong

AI Thread Summary
To determine the minimum current needed for a 1.00 m long copper rod with a mass of 50.0 g to float in a 1.00 T magnetic field, the equation mg = BIL is used. The correct calculation yields a current of approximately 0.4905 A. A misunderstanding arose when one participant miscalculated the mass, leading to a discrepancy in the answers provided. The confusion was clarified, highlighting the importance of accurate unit conversion. Accurate calculations are crucial for solving physics problems involving magnetic fields.
kevinlikesphysics
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4. [SFHS99 21.P.37.] A thin 1.00 m long copper rod has a mass of 50.0 g. What is the minimum current needed in the rod to cause it to float in a magnetic field of 1.00 T?i got 4.9 what am i doing wrong i used ma =BiL

can someone tel me what I am doign wrong
 
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I got:

mg = BIL
I = \frac{mg}{BL} \Rightarrow I = \frac{0.05\times 9.81}{1\times 1}

I = 0.4905 A

Same as you.
? :confused:
 
Last edited:
why do you say the answer is wrong?
 
physicsprasanna said:
why do you say the answer is wrong?

Well, in case it's escaped notice, Hootenanny's answer is 1/10 of kevinlikesphysics'. I'm assuming that kevinlikesphysics simply converted the 50.0 g incorrectly.

-Dan
 
Ahhh, indeed. I miss read. I feel rather stupid now.
 

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