# Radioactive Nuclear Polonium Battery Question

• elliottmarter
Po 210 would have a half life of 5.6 yrs so the power output after 1 year would be 320 x 5.6 / 1.05 = 590W

#### elliottmarter

Question

The α-emitter 210, 84 Po is used in a nuclear battery. The kinetic energy of the emitted alpha particles can be worked out from energy and momentum conservation. It is converted into electrical energy at 5.0% efficiency.

(a) Determine the initial power output (in W) of the battery if it contains 320 g of 210, 84 Po. Look "www.google.com/search?hl=en&q=210+Po+nuclear+decay"[/URL] (for instance) for relevant data.

(b) Determine the power output (in W) of the battery in (a) after 1 year of operation.

[RIGHT][8 marks][/RIGHT]

not sure if anyone agrees with me on this one, but this work is worth 40% of the entire module and they have the cheek to link me to a google search and effectively tell me to find all the necessary values myself, i wasn't impressed...especially when you think that you might have the knowledge to do the question and just not know where to find reliable values from...

(a) well i would firstly use [B]kinetic energy = 1/2 mv[SUP]2[/SUP][/B] where m=mass of an alpha particle and v=emission speed then times that by amount emitted per second (activity) to get an answer in joules per second (ie Watts) then times by 0.05 for an efficiency factor of 5%

(b) find the half life of 210, 84 Po and use [B]N = N[SUB]0[/SUB] e[SUP]-$$\lambda$$ t[/SUP][/B] to find the number of nucleons left after one year then use [B]R=$$\lambda$$ N[/B] for the activity after one year, then simply repeat the method for question (a)...

i appreciate that these might be the right methods but i posted this in order to give you an idea of what values I'm searching for, if I am wrong in the solutions above please say.

any feedback would be much appreciated, thanks guys

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Everything you said looks correct to me. Probably when you look up the alpha emission of Po-210, you will find the alpha emission energies directly, so you won't need to use E=1/2 mv^2.

Thanks for the reply phyzguy i was thinking i needed loads of extra info but now i realize the only bit of information about Po 210 that I could find online would be its half life as the activity and decay constant etc etc etc depend on how much of the stuff is left in this case 320g