# Problem: A container holds a pure sample of a radioactive substance with a half-life of 2 hours.Which of the following statements are true?a) After 1 hour, less than 50% of the original atoms in the container will have decayed.b) After 1 hour, more than 50% of the original atoms in the container will have decayed.c) After 2 hours, 50% of the original atoms in the container will have decayed.d) After 4 hours, 25% of the original atoms will have decayed.e) After 4 hours, the total number of atoms in the container will be reduced by 75%.

###### FREE Expert Solution

The number of atoms remaining after every half-life:

$\overline{){\mathbf{N}}{\mathbf{=}}{{\mathbf{N}}}_{{\mathbf{0}}}{{\mathbf{\left(}}\frac{\mathbf{1}}{\mathbf{2}}{\mathbf{\right)}}}^{\mathbf{\left(}\mathbf{t}\mathbf{/}{\mathbf{t}}_{\mathbf{1}\mathbf{/}\mathbf{2}}\mathbf{\right)}}}$

After 2 hours:

N = N0(1/2)(2/2) = 0.5N0

84% (153 ratings) ###### Problem Details

A container holds a pure sample of a radioactive substance with a half-life of 2 hours.
Which of the following statements are true?

a) After 1 hour, less than 50% of the original atoms in the container will have decayed.
b) After 1 hour, more than 50% of the original atoms in the container will have decayed.
c) After 2 hours, 50% of the original atoms in the container will have decayed.
d) After 4 hours, 25% of the original atoms will have decayed.
e) After 4 hours, the total number of atoms in the container will be reduced by 75%.

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