Magnetic field questionwhat did i do wrong

[kevinlikesphysics]

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

 

[Hootenanny]

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.
?

 

[physicsprasanna]

why do you say the answer is wrong?

 

[topsquark]

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

 

[Hootenanny]

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