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The half-life of the radioactive substance is 40 days. The substance will disintegrate completely in

#### Options

40 days

400 days

4000 days

infinite time

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#### Solution

**infinite time**

**Explanation:**

The time it takes for a substance to completely dissolve is infinite.

log`"N"_0/0 = λt`

⇒ log`"N"_0/0 = λt`

log ∞ = λt

hence when N → 0, t → ∞

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