dear Loo Kian Sing . very thanks for your interested question
in your case if the pressures are the same in both cases = P1 . the pressure losses in the second case will be higher than the first case because of increase in fraction losses in second case due to decrease in diameter so p2 in the first line will be higher than be p2 in the second line

with reference to your second inquiry the following link can clear it for us

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regards