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# I'm being a bit slow but just started nuclear physics and can't do this question watch

1. If 45% of the unstable nuclei in a sample take 50s to decay, calculate the decay constant in s−1.

need an explanation on how to do it!

Josh
2. bumo
3. N=N0e^(-lambda*t)

45% of nuclei decay so number of nuclei remaining, N=0.55N0.

0.55N0=N0e^(-lamda*50)

Rearrange and solve for lambda.

Let me know if the formatting is any good.

Hope that helped. If not let me know.
4. You can use the equation: 𝑁 = 𝑁oe−𝜆t but since it says 45% of the nuclei have decayed then N/No = 0.45

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