Test Index

NCERT Class XII Chapter
Dual Nature of Radiation and Matter
Questions With Solutions

© examsnet.com
Question : 16 of 37
Marks: +1, -0
An electron and a photon each have a wavelength of 1.00 nm. Find
(a) their momenta,
(b) the energy of the photon, and
(c) the kinetic energy of electron.
Solution:  
(a) Momentum for both electron and photon will be same for same wavelength.
p = hλ\frac{h}{\lambda} = 6.63×10−3410−9\frac{6.63 \times 10^{-34}}{10^{-9}} = 6.63 × 10−2510^{-25} kg m s−1s^{-1}
(b) Energy of photon E = hv = hcλ\frac{hc}{\lambda}
E = 6.63×10−34×3×10810−9×1.6×10−19\frac{6.63 \times 10^{-34} \times 3 \times 10^{8}}{10^{-9} \times 1.6 \times 10^{-19}} = 1.24 KeV
(c) Kinetic energy of electron
K = p22m\frac{p^{2}}{2m} = (6.63×10−25)22×9.1×10−31\frac{(6.63 \times 10^{-25})^{2}}{2 \times 9.1 \times 10^{-31}} = 2.42 × 10−1910^{-19} J
= 2.42×10−191.6×10−19\frac{2.42 \times 10^{-19}}{1.6 \times 10^{-19}} eV = 1.51 eV
© examsnet.com
Go to Question:
Prev Question
Next Question