# Hydrogen bonding

It is mentioned in my textbook:

"Hydrogen atoms of water molecule create strong electrical field due to their small sizes"

How is the size related to electrical field and its strength?

A little touch of physics will be greatly appreciated.

The magnitude of the electric field is basically given by Coulomb's law. In SI units, the electric field $E$ at the distance $r$ from the charge $Q$ is $$E = \frac{Q }{4\pi \epsilon_0 r^2}$$ The sentence only says the simple point that if $r$ (distance from the charge, in this case the proton i.e. nucleus) which is squared in the denominator is short, then the electric field will be large (strong) because it's the inverse square law (involving indirect proportionality).