(adsbygoogle = window.adsbygoogle || []).push({}); Energy Problem--what did I do wrong???

Fusion (or "thermonuclear") reactions take place inside a star such as our Sun. One fusion reaction results from a collision between a proton (1H) and a deuteron (2H, the nucleus of "heavy" hydrogen, consisting of a proton and a neutron). When these two nuclei touch, they undergo a nuclear reaction, forming a helium-3 (3He) nucleus (containing two protons and one neutron) and a high energy photon, called a gamma ray.

1H + 2H 3He +

One "unified atomic mass unit", denoted by the symbol "u", is equal to 1.66 10-27 kg. The rest mass of the proton is 1.0073 u, the rest mass of the deuteron is 2.0136 u, the rest mass of the helium-3 nucleus is 3.0155 u, and the gamma ray is massless.

so....

rest masses

proton = 1.0073 u

deuteron = 2.0136 u

helium-3 nucleus = 3.0155 u

What is the kinetic energy of the helium nucleus plus the energy of the photon in the final state? Because you will be calculating a small difference of large quantities, you will need to use 5 or more significant figures in this calculation.

KHe + E = joules

*I've aready found out that the equation is:

mprotonc^2 + mdeuteronc^2 +Ui = mheliumc^2 +Khelium + Egamma

*Eand earlier in the problem I got that the Ui between the proton and the deuteron is 1.152e-13 J

so to find out mc^2 for the proton, deuteron, and helium,

(for the proton)

= (1.0073u) *(1.66e-27 kg) *(3e8)^2 = 1.5049062 J

(for deteron)

= 3.0083184 J

(for helium)

= 4.505158 J

so you would sove for Khelium + Egamma and get

Khelium + Egamma = mprotonC^2 +mdeutronC^2 +Ui - mheliumc^2

and i get 9.5876e-13....which is wrong?

Where have I gone wrong? Any help is greatly appreciated!!! thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Energy Problem-what did I do wrong?

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**