Exponent of units digit – UGC NET Question

In a positional decimal system, the rightmost digit is in the units place. Its positional weight is 10^0, which equals 1. Multiplying the digit by 10^0 leaves its value unchanged, reflecting that it counts units. Hence the exponent for the rightmost digit is 0.

Option A:
Option A is correct because any number raised to the power 0 equals 1, and the units place must have a weight of 1. This matches how we interpret the rightmost digit in any decimal number.

Option B:
Option B, exponent 2, would give a weight of 10^2 = 100, which belongs to the hundreds place, not the units place. Assigning 10^2 to the rightmost digit would distort the positional structure.

Option C:
Option C, exponent 3, yields 10^3 = 1000, corresponding to the thousands place. This is far from the unit's role and clearly inappropriate.

Option D:
Option D, exponent 1, represents the tens place, where each digit counts groups of ten. The rightmost digit is not in this position, so exponent 1 is not correct for it.