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Physical World

Question
CBSEENPH11020740

If the lattice parameter for a crystalline structure is 3.6 A, then atomic radius in fcc crystal is

  • 1.18 A

  • 2.10 A

  • 2.92 A

  • 1.27 A

Solution

D.

1.27 A

Atomic radius is the distance between two nearest neighbours. For Fcc crystal 

Atomic space radius space equals space fraction numerator 1 over denominator 2 square root of 2 end fraction space straight x space lattice space parameter
or space space straight r space equals space fraction numerator straight a over denominator 2 square root of 2 end fraction
straight r equals space fraction numerator 3.6 over denominator 2 square root of 2 end fraction space straight A to the power of straight o space equals space 1.27 space straight A to the power of straight o