Question
A radioactive substance decays from 2.0kg to 1.6kg in 156 days.
How much will be left after 201 days?
How much will be left after 201 days?
Answers
Elena
N₁=N₀exp(-λt₁)
N₁/N₀ = exp(-λt₁)
ln(N₀/N₁) =λt₁
λ = ln(N₀/N₁)/t₁=
=ln(2/1.6)/156=0.223/156 (day⁻¹)
N₂=N₀exp(-λt₂) =
=2•exp(-0.223•201/156)=2•0.75 =1.5 kg
N₁/N₀ = exp(-λt₁)
ln(N₀/N₁) =λt₁
λ = ln(N₀/N₁)/t₁=
=ln(2/1.6)/156=0.223/156 (day⁻¹)
N₂=N₀exp(-λt₂) =
=2•exp(-0.223•201/156)=2•0.75 =1.5 kg