Q. Consider an electron $(m = 9.1 \times 10^{- 31}kg)$ confined by electrical forces to move between two rigid walls separated by $1.0 \times 10^{- 9}metre$, which is about five atomic diameters. The quantized energy value for the lowest stationary state is
A) $12 \times 10^{- 20}joule$
B) $6.0 \times 10^{- 20}joule$
C) $6.0 \times 10^{- 18}joule$
D) $6\ joule$
Explanation
(b) It will form a stationary wave
$\lambda = 2l = 2 \times 10^{- 9}m$
$\Rightarrow \lambda = \frac{h}{\sqrt{2mE}}$
$\Rightarrow E = \frac{h^{2}}{2m\lambda^{2}} = 6 \times 10^{- 20}J$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.