JEE Main & Advanced
Sample Paper
JEE Main Sample Paper-42
question_answer
Electrons having KE 15 eV is collided with hydrogen atom and 80.6% of it is used to excite the electrons from its ground state. Find the number of emitted wavelengths.
A) 1
B) 2
C) 3
D) 4
Correct Answer:
C
Solution :
\[\frac{80.6}{100}\times 15=\Delta E\] \[=12.09\] \[=|{{E}_{3}}-{{E}_{1}}|\] So, \[{{e}^{-1}}\]can make the hydrogen atom to go into 2nd exited state ie, n = 3 energy state. From this 3 transitions are possible ie, from 3 to 2, 3 to 1 and 2 to 1.