Answer: Twice its original value.
Explanation:
From Ohm's law, current is directly proportional to the voltage.
I ∝ V
V = I R
Keeping voltage constant, Current is inversely proportional to resistance.
I ∝ 1/R
[tex]V = \frac{I}{2}R'\\ \Rightarrow R'= \frac{2V}{I} =2 R[/tex]
When current is cut to half the original, the resistance should be increased to twice its original value to keep the voltage constant.