Answer
(a) bulb A
(b) 4
Work Step by Step
(a) We know that
$P=VI$
$P_A=4P_B$ (according to given condition)
$\implies V_AI=4V_BI$
$\implies V_A=4V_B$
Thus bulb A has greater potential difference as compared to that of bulb B.
(b) We know that
$P=VI$
$P_A=4P_B$ (according to given condition)
$\implies V_AI=4V_BI$
$\implies V_A=4V_B$
$\implies \frac{V_A}{V_B}=4$
This is the required ratio.
