Student Login

Home›Chapters›Nuclear Physics PYQs›Law of Radioactive Decay›Question 113

NEET 2003 (AIPMT) · Law of Radioactive Decay

Law of Radioactive Decay question from NEET 2003 (AIPMT)

Q113NEET 2003 · AIPMTMedium

Law of Radioactive Decay

A sample of radioactive element has a mass of 10 g at an instant t = 0. The approximate mass of this element in the sample after two mean lives is

Show answer and solution

Answer: (a)

Mean life $\tau = \frac{1}{\lambda}$ , so after $t = 2\tau$ : $m = m_0e^{-2}$ .
$m = 10\times0.135 = 1.35$ g.
So the answer is (a) 1.35 g.

Report a mistake

More questions on Law of Radioactive Decay

A radioactive sample at any instant has its disintegration rate 5000 disintegrations per…JEE Main 2003 (AIEEE)
A sample of radioactive element containing 4 × 1016 active nuclei. Half life of element…NEET 2002 (AIPMT)
If N₀ is the original mass of the substance of half-life period t1/2 = 5 years, then the…JEE Main 2002 (AIEEE)
Half life of a radioactive element is 12.5 hour and its quantity is 256 g. After how much…NEET 2001 (AIPMT)
Half-life period of a radioactive substance is 6 h. After 24 h activity is 0.01, what was…NEET 2001 (AIPMT)
The half-life of a radioactive material is 3 h. If the initial amount is 300 g, then…NEET 2000 (AIPMT)
The relation between λ and T1/2 as (T1/2 → half life)NEET 2000 (AIPMT)
Half-lives of two radioactive substances A and B are respectively 20 min and 40 min…NEET 1998 (AIPMT)