Computer systems manipulate bit patterns.
Convert the denary number 140 to 8-bit binary.
Mark scheme
Award one mark for each correct nibble in the correct order:
- 1000 (1)
- 1100 (1)
0 marks if the response is not 8-bit binary.
Example answers and how they were marked
Full marks2/2
1000 1100
Why: 140 = 128 + 8 + 4: both nibbles are correct (2).
Some marks1/2
1000 1101
Why: Converts 141 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.
No marks0/2
0011 0001
Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.