Which out of `NH_(3)` and `NF_(3)` have higher dipole moment and why?

Explanation

In `NH_(3)" and " NF_3` both the molecules have pyramidal shape with a lone pair of electrons on nitrogen atom. The fluorine is more eletronegatibe than nitrogen, but the resultant dipole moment of `NH_3` is greater than that of `NF_3`. This is because , in case of `NH_3` the orbital dipole due to lone pair is in the same direction as the resultant dipole moment of N-H bonds. but in `NH_3`, the orbital dipole is in direction opposite to that of three N-F bonds. this decreases the resultant N-F bond moments.