UGC NET Questions (Paper – 1)

An 8-bit unsigned binary number has 2⁸ distinct combinations. These combinations represent integer values starting from all zeros to all ones. Therefore, the smallest value is 0 and the largest is 2⁸ − 1 = 255. Hence, the full representable range is from 0 to 255 inclusive.

Option A:
Option A correctly applies the formula for unsigned range, 0 to 2ⁿ − 1, with n = 8. This gives 0 to 255, accounting for all 256 possible patterns of bits. It therefore captures the correct closed interval of values.

Option B:
Option B, 1 to 255, excludes the all-zero pattern which clearly corresponds to 0. Omitting 0 contradicts the fact that 00000000₂ is a valid 8-bit representation. Thus, this range is incomplete and incorrect.

Option C:
Option C, 0 to 256, includes an upper bound of 256 which would require nine distinct states above 0, exceeding the count of 256 bit patterns. Since 256 equals 2⁸, it cannot be represented as the maximum; the correct maximum is one less.

Option D:
Option D, 1 to 256, is doubly incorrect because it both omits 0 and includes 256 as a representable value. This overstates the range at the upper end and understates it at the lower end.