A simple physics 12 question

[invinc1ble]

I don't know if this is the place to post this, but This is a simple Grade 12 Physics question that I have been working on for about half an hour now.

For those who don't normally use this notation,
2E10 = 2X10^10.
2E-2 = 2X10^-2

"A magnetic field of 3.4E-3T deflects electrons into a circular path of radius .014m. The electorns have been accelerated through a potential differenc eof 250V. If the charge of an electron is 1.6E-19C, what is the mass of the electron?"

I have done it three times, and I keep getting 7.25E-31Kg when in actuality, a real electron is 9.11E-31Kg

[chroot]

Do you really mean 3,400 tesla? I doubt it.

- Warren

[invinc1ble]

sorry.. i'd make that 3.4E-3T
(.0034)

[chroot]

Well, I derived

m = \frac{B^2 q (2 r)^2}{8 V}

and got the same answer you got:

http://www.google.com/search?num=30&hl=en&lr=&ie=UTF-8&safe=off&c2coff=1&q=%28%283.4+*+10%5E-3+tesla%29%5E2+*+1.60+*+10%5E-19+coulombs+*+%28%282+*+0.014%29+meters%29%5E2%29+ %2F+%288+*+250+volts%29&btnG=Search

Are you sure the problem was copied down properly?

- Warren

[invinc1ble]

I did this question from a worksheet, and we both got identical answers.

If you have the same answer that my friend and I do, then chances are it is correct.

Thanks for your help!