Physics Exam-Style Question Help please

If anyone could help me with this question I would be very thankful.

1) In a radioactive decay of a nucleus a B+ particle is emitted followed by a Y photon of wavelength 8.30x10^-13.

a) State the rest mass of the B+ particle in Kg.

For this I used c/wavelength = f
3.00x10^8/8.30x10^-13 = 3.61x10^20 Hz

E=hf
E = 6.63x10^-34 * 3.61x10^20 = 2.40x10^-13J

m=E/c^2
m=2.40x10^-13/9.00x10^6 = 2.7x10^-30Kg

The problem with this is that I don't think this is right as i got told the that the mass of an electron was 9.11x10^-31. So if you know where/what I did wrong I would be grateful. Thanks.

Reply 1

98bethanylouise

youre not calculating the mass of an electron, i had the exact same question and came out with the same answer and its right

Reply 2

hi2021me

But the frequency you're using is for the photon and not the beta particle.Hi, sorry but I'm also stuck on this question and I just don't understand your working out.