If the magnitude of the electrostatic force felt by a charge is three times that from another charge, but their charges are the same, then the electric field strength of this charge is the strength of the other charge.
three times
nine times
one-third
one-ninth

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods