Finding mass of a radioactive sample from MeV and Bq

[bayan]

I wanted to know how to find the mass of a radioactive sample given its Energy "MeV" and and decay rate "Bq"?
Can you please give me a hand with this one by giving me the formula.

Please don't solve an example because this is part of my case study.

Thanks a lot

 

[Chi Meson]

Some details: is the radioactive object moving? If not, then it's energy (in eV) corresponds to its mass using a certain well-known equation (E=mc^2). BUt in order to get kg, you need to convert eV to joules (1eV = 1.602 x 10^-19 joules).
If the radioactive sample is moving then you need to do a little more.

I'm not familiar with decay rate as "Bq." Usually the decay constant is represented by a greek "lambda." Could you specify what the B and the q represent?

 

[bayan]

thanx

I thought there was a harder way.

i had that in mind but usualy what i think at the end i might get the same answer but since the formula is diffrent i lose marks.