Why Are My Particle Physics Calculations Incorrect?

[bobo343]

I'm currently studying physics at A-level, and for particle physics I'm fine about the theory of the equations, I remember what equations to use etc, but I can't seem to get the right answers from my calculator.

For example, when working out the specific charge of a carbon ion with Z = 6, A = 13 and a charge of 2+, the necessary equation would be Specific Charge = charge/mass.

Which is: 2 x 1.60 x 10^-19 / 6 x 1.67 x 10^-27 + 7 x 1.67 x 10^-27 + 4 x 9.11 x 10^-31

When shortened is: 2 x 1.60 x 10^-19 / 13 x 1.67 x 10^-27

Which finally should = 1.47 x10^7 C kg^-1

But when I enter 2 x 1.60 x 10^-19 / 13 x 1.67 x 10^-27 into my calculator, I get a vastly different answer of 4.110769231 x 10^-47

Is there something I'm doing wrong? We haven't done particle physics in a while and I might be missing a vital step.

Any help will be greatly appreciated.

 

[Stonebridge]

I suggest you use brackets around the terms to ensure your calculator is doing exactly what you want it to.
(2x1.6x10^-19) / (13x1.67x10^-27)
and try again now.

 

[bobo343]

Alright, with the brackets I get 14739751.27.

Is there any way I can set my calculator to give me the answer with the x10^n? (n just being whatever power)

Thanks for the help.

 

[tomwilliam]

It depends on the calculator, but mine has a "scientific" setting, where the results in exponentials come up as e.g. 3.4567Exp8.
It's probably not a bad idea to practise putting things in the right scientific notation anyway though.