The activity of a radioactive material is 6.4 × 10-4 curie. Its half life is 5 days. The activity will become 5 × 10-6 curie after
- 7 days
- 15 days
- 25 days
- 35 days
The Correct Option is D
Solution and Explanation
The correct answer is (D) : 35 Days
\(∵ A = \frac{A_0}{\frac{t}{2^{T_{1/2}}}}\)
\(⇒ 2^{t/5} = \frac{6.4×10^{-4}}{5×10^{-6}}\)
\(= 128 = 2^7\)
\(⇒ \frac{t}{5} = 7\)
⇒ t = 35 days
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Concepts Used:
Radioactivity
Radioactivity is a phenomenon observed in certain elements where unstable atomic nuclei spontaneously emit energy and subatomic particles. This process is driven by the desire of the nucleus to achieve a more stable state. It's crucial to understand the three main types of radioactive decay:
Alpha Decay: In alpha decay, a nucleus emits an alpha particle, consisting of two protons and two neutrons.
Beta Decay: Beta decay involves the emission of a beta particle, which can be a positron or an electron, from an unstable nucleus.
Gamma Decay: Gamma decay releases gamma rays, electromagnetic radiation, to achieve a more stable nuclear state.
The emission of these particles and energy is a result of nuclear instability. The rate of decay is characterized by the half-life, the time taken for half of the radioactive material to undergo decay. Radioactivity has diverse applications, from medical treatments and industrial processes to power generation in nuclear reactors.