The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centered cubic unit cell are _ respectively :
Correct answer: A. 1,4,2
- A. 1,4,2
- B. 4,1,2
- C. 2,4,1
- D. 4,8,2
Explanation
The number of atoms per unit cell in a simple cubic, face-centered cubic and body-centred cubic unit cell are 1,4,2 respectively.(1) The number of atoms contained in a simple cubic unit cell of monoatomic substance is 1.8 atoms are present at 8 corners of a simple cubic unit cell. Each atom contributes one eigth to the unit cell. Total contribution = 8/8 = 1(2) The number of atoms contained in one face-centred cubic unit cell of monoatomic substance is 4.8 atoms are present at 8 corners of a face-centred cubic unit cell. Each atom contributes one eigth to the unit cell. Total contribution = 8/8 = 16 atoms are present at 6 corners of a face-centred cubic unit cell. Each atom contributes one half to the unit cell. Total contribution = 6/2 =3Total number of atoms in one face-centred cubic unit cell = 1+3= 4.(3) The number of atoms contained in a body-centred cubic unit cell of monoatomic substance is 2.8 atoms are present at 8 corners of a body-centred cubic unit cell. Each atom contributes one eigth to the unit cell. Total contribution = 8/8 = 11 atom is present at body centre of a body-centred cubic unit cell. The atom contributes fully to the unit cell. Total contribution = 1×1 =1Total number of atoms in one body-centred cubic unit cell = 1+1= 2.
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