NEET 2015
- Exam
- NEET
- Year
- 2015
- Subject
- Physics
- Chapter
- Dual Nature of Matter
NEET 2015 · Physics · Dual Nature of Matter
Light of wavelength 500nm is incident on a metal with work function...
Light of wavelength is incident on a metal with work function . The de Broglie wavelength of the emitted electron is:
Options
- A
- B
- C
- D
Correct answer
B.
Step-by-step solution
K{E}_\max = \dfrac{hc}{\lambda} - Ψ
⇒ K{E}_\max = \dfrac{1240}{500} - 2.28
⇒ K{E}_\max = 2.48 - 2.28 = 0.2eV
{\lambda}_\min = \dfrac{h}{\sqrt{2m{\left(KE\right)}_\max}} = \dfrac{\dfrac{20}{3} \times {10}^{- 34}}{\sqrt{2 \times 9 \times {10}^{- 31} \times 0.2 \times 1.6 \times {10}^{- 19}}}
{\lambda}_\min = \dfrac{25}{9} \times {10}^{- 9} = 2.80 \times {10}^{- 9}m
So, .
⇒ K{E}_\max = \dfrac{1240}{500} - 2.28
⇒ K{E}_\max = 2.48 - 2.28 = 0.2eV
{\lambda}_\min = \dfrac{h}{\sqrt{2m{\left(KE\right)}_\max}} = \dfrac{\dfrac{20}{3} \times {10}^{- 34}}{\sqrt{2 \times 9 \times {10}^{- 31} \times 0.2 \times 1.6 \times {10}^{- 19}}}
{\lambda}_\min = \dfrac{25}{9} \times {10}^{- 9} = 2.80 \times {10}^{- 9}m
So, .