Answer
(a) $ I_1=I_2=I_3$
(b) $ V_1\lt V_2 \lt V_3$.
Work Step by Step
(a) We know that the same amount of current is passing though the given three resistors because they are connected in series. Thus, the required order is $ I_1=I_2=I_3$.
(b) Since the resistors are connected in series, the potential difference is not the same and we know that $ V\propto R $. Hence the resistors can be ranked in order of increasing potential difference as $ V_1\lt V_2 \lt V_3$.
