question_answer 74)

      The percentage of empty space in a body centred cubic arrangement is (a) 74            (b) 68            (c) 32            (d) 26

Answer:

                                                                        (c) Packing efficiency for bcc arrangement is 68% which represents total filled space in the unit cell. Hence, empty space in a body centred arrangement is 100 - 68 = 32 %. Note Here, empty space in bcc arrangement is asked therefore empty space in any crystal packing can be calculated as empty space in unit cell =100 ? packing efficiency