| ⇦ | 
| ⇨ |
The half life of radioactive isotope ‘X’ is 50 years. It decays to another element ‘Y’ which is stable. The two elements ‘X’ and ‘Y’ were found to be in the ratio of 1 : 15 in a sample of a given rock. The age of the rock was estimated to be
Options
(a) 150 years
(b) 200 years
(c) 250 years
(d) 100 years
Correct Answer:
200 years
Explanation:
Let no. of atoms in X = Nₛ, No. of atoms in Y = Nₜ
By eq. Nₛ / Nₜ = 1/15
Part of Nₛ = 1/16 (Nₛ + Nₜ) = 1/2⁴ (Nₛ + Nₜ)
So, total 4 half lives are passed, so, age of rock is 4 x 50 = 200 years.
Related Questions: - In which of the following systems will the radius of the first orbit (n=1) be minimum?
- What is the voltage gain in a common-emiiter amplifier, when input resistance is 4 Ω
- A solenoid of length l metre has self inductance L henry. If number of turns
- A wave in a string has an amplitude of 2cm. The wave travels in the positive direction
- The moment of inertia of a uniform circular disc of radius R and mass M about an axis
Topics: Radioactivity
(83)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- In which of the following systems will the radius of the first orbit (n=1) be minimum?
- What is the voltage gain in a common-emiiter amplifier, when input resistance is 4 Ω
- A solenoid of length l metre has self inductance L henry. If number of turns
- A wave in a string has an amplitude of 2cm. The wave travels in the positive direction
- The moment of inertia of a uniform circular disc of radius R and mass M about an axis
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.
Share this page with your friends
Leave a Reply