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PhysicsModern PhysicsRadioactivityEasy2 minPYQ_2020
PhysicsEasysingle choice

A mixture consists of two radioactive materialsA1andA2with half-lives of20 sand10 s, respectively. Initially, the mixture has40 gofA1and160 gofA2. The amount of the two in the mixture will become equal after

Options:

Answer:
D
Solution:

Let after time t s, A1and A2will become equal in the mixture.

As N⁡ = N⁡ 0 1 2 n

where n is the number of half-lives

For A⁡ 1, N⁡ 1 = N⁡ 0 1 1 2 t / 2 0

For A⁡ 2, N⁡ 2 = N⁡ 0 2 1 2 t / 1 0

According to question,N1=N2

4 0 2 t / 2 0 = 1 6 0 2 t / 1 0

2 t / 1 0 = 4 2 t / 2 0 or 2 t / 1 0 = 2 2 2 t / 2 0

2 t / 1 0 = 2 t 2 0 + 2

t 1 0 = t 2 0 + 2 or t 1 0 - t 2 0 = 2

ort20=2ort=40 s

Stream:NTA_ABHYAS_NEETSubject:PhysicsTopic:Modern PhysicsSubtopic:Radioactivity
⏱ 2mℹ️ Source: PYQ_2020

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