Find the values of `ointvecB.vecdl` for the loops `L_(1),L_(2),L_(3)` in the figure shown . The sence of `vecdl` is mentioned in the figure.

Explanation

for `L_(1)ointvecB*vecdl=mu_(0)(I_(1)-I_(2))`
here `I_(1)` is taken positive because magnetic lines of force produced by `I_(1)` is anti clockwise as seen from top . `I_(2)` produced lines of `vecB` in clockwise sense as seen from top . The sense of `vecdl` is anticlockwise as seen from top .
for `L_(2):ointvecB*vecdl=mu_(0)(I_(1)-I_(2)+I_(4))`
for `L_(3):ointvecB*vecdl=0`