UGC NET Questions (Paper – 1)

Binary Coded Decimal encodes each decimal digit separately as a 4-bit binary value. This allows decimal digits 0 through 9 to be represented by binary patterns from 0000₂ to 1001₂. Using 4 bits per digit is sufficient and convenient for hardware that interfaces with decimal displays. Therefore, each BCD digit occupies 4 bits.

Option A:
Option A, 3 bits, can represent only 8 distinct values, which is insufficient for ten digits 0 through 9. Thus, 3 bits cannot encode all decimal digits in BCD.

Option B:
Option B, 2 bits, allows only 4 combinations and is even more inadequate. It cannot uniquely represent all decimal digits.

Option C:
Option C is correct because 4 bits give 16 combinations, enough for digits 0–9 and some unused patterns. This is the standard sizing for BCD fields.

Option D:
Option D, 8 bits, would be wasteful for representing a single decimal digit, since 8 bits can represent 256 different values. BCD typically keeps the encoding compact with 4 bits per digit.