⇦ | ⇨ |
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: - Water rises to a height h in a capillary at the surface of earth. On the surface
- A metal rod of length l cuts across a uniform magnetic field B with a velocity v.
- In a common emitter (CE) amplifier having a voltage gain G, the transistor
- If two slits in Young’s experiment are 0.4 mm apart and fringe width on a screen
- In the given figure, a diode D is connected to an external resistance R=100 Ω
Topics: Radioactivity
(83)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- Water rises to a height h in a capillary at the surface of earth. On the surface
- A metal rod of length l cuts across a uniform magnetic field B with a velocity v.
- In a common emitter (CE) amplifier having a voltage gain G, the transistor
- If two slits in Young’s experiment are 0.4 mm apart and fringe width on a screen
- In the given figure, a diode D is connected to an external resistance R=100 Ω
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