(a) Convert \(1011011_2\) to hexadecimal
Method 1 (through denary):
\[1011011_2 = (1\times2^6)+(0\times2^5)+(1\times2^4)+(1\times2^3)+(0\times2^2)+(1\times2^1)+(1\times2^0)\]
\[= 64+0+16+8+0+2+1 = 91_{10}\]
Dividing 91 repeatedly by 16: \(91 = 5\times16 + 11\), where \(11 = \text{B}\). Reading the digits gives \(5\text{B}\).
Method 2 (direct grouping): group the bits in fours from the right, \(0101\;1011\). Then \(0101 = 5\) and \(1011 = \text{B}\).
Therefore \(1011011_2 = 5\text{B}_{16}\).
(b) One difference between a hacker and a scammer
A hacker is a person who uses backend technical knowledge of software to gain unauthorised access to the computer systems or accounts of unsuspecting users, with the aim of stealing, altering or exploiting data. A scammer deceives victims through confidence tricks, sending unwanted or inappropriate electronic messages to many recipients, or luring the victim into granting remote access, in order to defraud them. In short, the hacker breaks in through technical means, while the scammer relies on deception to make the victim hand over money or information.
(c) Parts labelled A, B, C and D on the keyboard
- A - Function keys (F1 to F12), the row along the top.
- B - Alphanumeric (typing) keys, the central QWERTY block of letters, numbers and symbols.
- C - Numeric keypad, the calculator-style block of number keys on the right.
- D - Cursor (arrow) control keys, used to move the pointer up, down, left and right.