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The decay constant of a radio isotope is λ. If A₁ and A₂ are its activities at time t₁ and t₂ respectively, the number of nuclei which have decayed during the time (t₁ – t₂):
Options
(a) λ (A₁ – A₂)
(b) A₁t₁ -A₂t₂
(c) A₁ – A₂
(d) (A₁ – A₂) / λ
Correct Answer:
(A₁ – A₂) / λ
Explanation:
Activity is given by A = dN/ dt = -λN
Activity at time t₁ is A₁ = – λN₁
and activity at time t₂ is A₂ = -1 N₂ as t₁ > t₂ therefore, number of atoms remained after time t₁ is less than that remained after time t₂.
That is, N₁ < N₂. number of nuclei decayed in (t₁ - t₂)
= N₂ - N₁ = (A₁ - A₂) / λ
Related Questions: - The binding energy of deutron is 2.2 MeV and that of ₂⁴He is 28 MeV.
- Light of wavelength 500 nm is incident on a metal with work function 2.28 eV.
- If a solid sphere of mass 1 kg and radius 0.1 m rolls without slipping at a uniform
- White light reflected from a soap film (Refractive Index =1.5) has a maxima
- A uniform force of (3i+j) Nacts on a particle of mass 2 kg.Hence the particle is displaced
Topics: Atoms and Nuclei
(136)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- The binding energy of deutron is 2.2 MeV and that of ₂⁴He is 28 MeV.
- Light of wavelength 500 nm is incident on a metal with work function 2.28 eV.
- If a solid sphere of mass 1 kg and radius 0.1 m rolls without slipping at a uniform
- White light reflected from a soap film (Refractive Index =1.5) has a maxima
- A uniform force of (3i+j) Nacts on a particle of mass 2 kg.Hence the particle is displaced
Topics: Atoms and Nuclei (136)
Subject: Physics (2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
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