Q. The ionisation energy of hydrogen atom is 13.6 eV. What will be the ionisation energy of $He^{+}$?
A) 13.6 eV
B) 54.4 eV
C) 122.4 eV
D) Zero
Explanation
(b)
Ionisation energy of $He^{+} = 13.6 \times Z^{2}\ eV$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = 13.6 \times (2)^{2}eV$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = 13.6 \times 4\ eV = 54.4\ eV$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.