Computers represent everything - text, photos, music - using just two digits, 0 and 1 (binary), instead of the ten digits people use every day. What is the main reason computer hardware is built this way?
- Because early programmers found binary easier to type than decimal numbers
- Because binary numbers take up less digital storage space than decimal numbers for representing the same value
- Because the tiny electronic switches inside a computer chip are far more reliable when built to represent just two clear states, like off and on, than when built to reliably tell apart ten finely graded voltage levels
- Because human eyes cannot easily distinguish between ten different symbols on a screen
Why C? And why not the others?
Correct answer: C. Because the tiny electronic switches inside a computer chip are far more reliable when built to represent just two clear states, like off and on, than when built to reliably tell apart ten finely graded voltage levels
Computer chips are built from millions of transistors, tiny electronic switches that work best when they only ever need to represent two clearly distinguishable states, such as 'on' (current flowing) and 'off' (no current). Building hardware that could reliably tell apart ten different voltage levels for ten decimal digits would be far more complex and error-prone than hardware that only has to distinguish two states, so binary became the natural fit for how physical circuits actually work. The option about typing convenience is wrong because the choice of binary has nothing to do with what is easy for a human to type; programmers rarely type raw binary at all, they write in higher-level languages that get translated down to binary. The option about storage space is wrong because representing the same value in binary generally takes more digits than in decimal, not fewer, so binary is not chosen to save space. The option about human eyesight is wrong because a computer's internal binary representation is never about what a human perceives on a screen; the digits 0 and 1 describe internal electrical states, not visible symbols.
Source: BBC Bitesize GCSE Computer Science: Systems architecture and data representation