Half-life Question ?!?!?!?!? (1 Viewer)

[sando]

i dont understand... :S

The mass, in grams, of a radioisotope substance is given by M = M₀e^-kt

I only need help with C... already figured out (a) and (B)

a) find Mo and k if a mass of 200kg decays to 195kg after 10 years
b) the rate of decay after 15 years

C) the half-life of the substance

 

[airie]

Is this maths? Looks morel ike chem or something

I don't know this formula, and I'm just assuming here that t is time measured in years, M₀ and k are constants, and e is the original mass measured in kg. (Which is not necessarily correct ) From this, sub M=200/2=100, e=200, and the values of M₀ and k that you found into the formula, and therefore find t in years.

^Just a suggestion, since I don't know what the letters in the formula represent nor their units of measurement

 

[Riviet]

Half-life is when the mass is half it's original mass, so find t when M=100kg

 

[fjholden]

If original weight not known Let M=0.5Mo.

 

[SoulSearcher]

Is this maths? Looks morel ike chem or something

Not chem, just exponential decay May be in chem though, don't do the course myself.

 

[sando]

ok.. thanks.. i just needed to know the meaning

i got the right answer now