Differential U tube manometer 

It is very helpful for my exams

Nice explanation sir!

I understand easily bro tq

Thank you Sir

even Pa and Pb at same level, the pressure is different ya? Pa not equal Pb directly. is it true?

But i have one doubt how you create the Differential pressure ,You dont use any equipment for create DPT, now the pipe line full same pressure inbetween the Pa and Pb need one orific plate

Why we are putting hd for pa -pb

Where are you bro ?