Answer and Explanation:
It is given that bulb A has the half the resistance as B
WHEN THEY ARE CONNECTED IN SERIES : In series circuit we know that current is same in the whole circuit
The power is given by [tex]P=i^2R[/tex] the expression it is clear that the bulb which has more resistance consume more power as current is same, and the bulb which consume more power will be brightest
It is given that resistance of bulb A is half the resistance of B So bulb A will be dimmest in this case
WHEN THEY ARE CONNECTED IN PARALLEL : In parallel circuit voltage is same across the circuit
The power is given by [tex]P=\frac{V^2}{R}[/tex] from the expression it is clear that the bulb which has least resistance will consume more power and so will be brightest
As the resistance of bulb A is less so it will be brightest in this case
