Mass of a particle through a magnetic field

[aChordate]

Homework Statement

In a mass spectrometer, the mass of charged objects is inferred from how much their trajectory curves when passed through a perpendicular magnetic field. A particle has a charge of q=1.602x10^-19 C and is traveling at v = 2.00x10^5 m/s in a perpendicular magnetic field of B=100gauss. If the radius of the curvature is found to be 20.8 cm, what is the mass of the particle? & can you identify this particle?

Homework Equations

F_c=mv²/r

The Attempt at a Solution

F_c=m(2.00x10^5 m/s)²/r

I am guessing this is proton because of the positive charge.

 

[aChordate]

Actually, I believe the equation is r= (mv)/(|q|B)

 

[aChordate]

So, (0.208m)=(m*2.00x10^5m/s)/(1.602x10^-19*0.1 tesla)

and m = 1.67 x 10^-26 kg

Is this correct?

 

[Dick]

So, (0.208m)=(m*2.00x10^5m/s)/(1.602x10^-19*0.1 tesla)

and m = 1.67 x 10^-26 kg

Is this correct?

0.1 tesla is 1000 gauss, not 100. Fix the exponent.

 

[aChordate]

It would be 0.01 Tesla and the answer would be 6.49x10^14 ?

 

[Dick]

It would be 0.01 Tesla and the answer would be 6.49x10^14 ?

It would be 0.01 tesla but now your answer is WAY off. You were closer before. What happened?

 

[aChordate]

I think I made an algebraic error.

Now I have m=1.67x10^-27

 

[aChordate]

And thanks for your help!