A mixture consists of two radioactive materials A₁ and A₂ with half lives of 20s

A Mixture Consists Of Two Radioactive Materials A And A Physics Question

A mixture consists of two radioactive materials A₁ and A₂ with half lives of 20s and 10s respectively. Initially the mixture has 40 g of A₁ and 160 g of A₂. The amount of the two in the mixture will become equal after:

Options

(a) 60 s
(b) 80 s
(c) 20 s
(d) 40 s

Correct Answer:

40 s

Explanation:

Let, the amount of the two in the mixture will become equal after t years.
The amount of A₁, which remains after t years N₁ = N₀₁ / (2)ᵗ/²⁰
The amount of A₂, which remains after t years N₂ = N₀₂ / (2)ᵗ/¹⁰
According to the problem N₁ = N₂
40 / (2)ᵗ/²⁰ = 160 / (2)ᵗ/¹⁰ ⇒ 2ᵗ/²⁰ = 2(ᵗ/¹⁰⁻²)
t/20 = t/10 – 2 ⇒ t/20 – t/10 = 2
t/20 = 2 ⇒ t = 40 s

Related Questions:

  1. A single slit Fraunhogger diffraction pattern is formed with white light.
  2. Power dissipated in an LCR series circuit connected to an a.c source of emf ? is
  3. Volume of gas becomes four times if temperature becomes
  4. Wires A and B are made from the same material. A has twice the diameter and three times
  5. 24 cells of emf 1.5 V each having internal resistance of 1 ohm are connected

Topics: Radioactivity (83)
Subject: Physics (2479)

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

NEETLab Mobile App

Share this page with your friends

Be the first to comment

Leave a Reply

Your email address will not be published.


*