Alpha, beta particle radius of curviture

[pat666]

Homework Statement

see attachment

Homework Equations

r=R_oA^1/3
R_o=1.2*10^-15

The Attempt at a Solution

35 kiloelectron volts = 5.60761762 × 10^-15 joules

I could calculate the velocity if I knew mass but that wouldn't help with the radius?
I think that I need to find A from the energy but how do I do that?

 

[rl.bhat]

The relevant equations are

mv^2/r = qvB. Or

mv = qrB.

sqrt(2mE) = qrB. where E is the energy of the particle , m is the mass of the particle.

Mass of β particle is the mass of the electron and mass of the α particle is equal to 4 times the mass of the proton.

 

[pat666]

Hey,
thanks that worked for the beta particle but not the alpha particle.
sqrt(2*4*1.6726E-27*5.61E-15)=1.602E-19*r*1.1 then I solved that and got 0.05m and that's wrong!

there's a similar Question in the textbook but the energy is 40keV and B=1.5T the answer in the textbook for the alpha particle is 19.3mm and when I try it I get 0.0525m?

thanks for helping!

 

[rl.bhat]

Hey,
thanks that worked for the beta particle but not the alpha particle.
sqrt(2*4*1.6726E-27*5.61E-15)=1.602E-19*r*1.1 then I solved that and got 0.05m and that's wrong!

there's a similar Question in the textbook but the energy is 40keV and B=1.5T the answer in the textbook for the alpha particle is 19.3mm and when I try it I get 0.0525m?

thanks for helping!

For alpha particle q = 2*e = 2*1.6*10^-19 C.

 

[pat666]

Thanks heaps - problem solved!