Explain why `BeH_(2)` molecule has a zero dipole moment although the `Be-H` bonds are polar?

Explanation

`BeH_(2)` is a linear molecule (H-Be-H) with bond angle equal to `180^(@)`. Aathough the Be-H bonds are polar on account of electronegativity difference between Be (1.5) and H (2.1) atoms, the bond polarities cancel with each other. The molecule has resultant depole moment of zero.