Atoms And Nuclei Question 266

Question: The wavelength Kα of X-rays for two metals ‘A’ and ?B? are 41875R and 1675R respectively, where ‘R’ is Rydberg constant. Find the number of elements lying between A and B according to their atomic numbers

Options:

A) 3

B) 1

C) 4

D) 5

Show Answer

Answer:

Correct Answer: C

Solution:

  • Using v 1λ=R(Z1)2[1n221n12] For α particle, n1=2,n2=1

    For metal A: 1875R4=R(Z11)2(34)Z1=26

    For metal B: 675R=R(Z21)2(34)Z2=31

    Therefore, 4 elements lie between A and B.



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