The Electron in a Hydrogen Atom Has an Orbital Radius $\times$

Multiple Choice

The electron in a hydrogen atom has an orbital radius of 0.0500 nm.To avoid being pulled into the nucleus by electrostatic attraction,the electron must have an orbital speed of

A) 7.12 km/s
B) 25.2 km/s
C) 1.02 $\times$ 10⁶ m/s
D) 2.25 $\times$ 10⁶ m/s
E) 5.0 $\times$ 10⁸ m/s