Hex digits for 20-bit binary – UGC NET Question

Each hexadecimal digit represents exactly 4 binary bits because base 16 equals 2⁴. To encode a 20-bit binary number, we divide 20 by 4 and obtain 5 hex digits. No fewer digits can cover 20 bits, while exactly 5 hex digits provide 5×4 = 20 bits of capacity. Therefore, the minimum number of hexadecimal digits required is 5, so option D is correct.

Option A:
Option A, 4 hex digits, cover only 16 bits, so they are insufficient for 20 bits.

Option B:
Option B, 6 hex digits, cover 24 bits; this is not minimum.

Option C:
Option C, 8 hex digits, cover 32 bits; far from minimum.

Option D:
Option D correctly matches 20 bits to 5 hex digits using 4 bits per hex digit.