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GATE 2018 ME (ME1) – Question 27

Engineering Materials · Crystal structure of common metals · 1 mark · Multiple choice

For an FCC crystal, atoms per unit cell and slip systems respectively are ______.

  1. 3 and 3
  2. 3 and 12
  3. 4 and 12
  4. 4 and 48

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Show answer and explanation

Correct answer: (C) 4 and 12

Explanation

FCC corners contribute $8(1/8)=1$ atom and faces $6(1/2)=3$, totaling 4. Four slip planes each have three slip directions, giving 12 systems. Answer C.