The best way to answer this question is by using a formula. The formula to use here is Absorbance= eLc (where e is the molar extinction coefficient, L is the path length, and c is the concentration of the solution). However, to answer this question, you need to understand Beer-Lambert's law.
According to Beer-Lambert's law, Absorbance is always proportional to the path length, provided the concentration of the solution and the molar extinction coefficient is kept constant. This is quite similar to this question, as both the concentration of the solution and the molar extinction coefficient are kept constant.
Since the value of the path length is reduced by half (from 2 to 1), the value of the absorbance will be reduced by half. This means if the value of the absorbance was recorded as 2.0, then it will be reduced by half to give 1.0.