Q. The total energy of an electron in the first excited state of hydrogen is about −3.4 eV. Its kinetic energy in this state is :
A) −3.4 eV
B) −1.7 eV
C) 1.7 eV
D) 3.4 eV
Explanation
[Solution from source] In a Bohr orbit KE = −E_total, so KE = +3.4 eV. Kinetic energy can never be negative, which rules out −3.4 eV and −1.7 eV. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.