Protons Are Being Accelerated in a Particle Accelerator $\sqrt { 2 }$

Multiple Choice

Protons are being accelerated in a particle accelerator. When the energy of the protons is doubled, their de Broglie wavelength will

A) decrease by a factor of 2 .
B) decrease by a factor of $\sqrt { 2 }$ .
C) increase by a factor of 2 .
D) increase by a factor of 4 .
E) increase by a factor of $\sqrt { 2 }$ .