KVPY2012PhysicsAtomic Physics
A metal is irradiated with light of wavelength 660 ~nm . Given that the work that the work function of the metal is 1.0 eV , the de Broglie wavelength of the ejected electron is close to -
Options
- A6.6 10⁻⁷ ~m
- B8.9 10⁻¹¹ ~m
- C1.3 10⁻⁹ ~m
- D6.6 10⁻¹³ ~m
Correct answer
C. 1.3 10⁻⁹ ~m
Step-by-step solution
array l E = + K . E E = hC = 6.6 10⁻³⁴ 3 10⁸ 660 10⁻⁹ =3 10⁻¹⁹ ~J =1 ev =1.6 10⁻¹⁹ ~J K.E. =3 10⁻¹⁹-1.6 10⁻¹⁹=1.4 10⁻¹⁹ ~J array for wave length of emitted electron = h 2 mKE = 6.6 10⁻³⁴ 2 9.1 10⁻³¹ 1.4 10⁻¹⁹ = 6.6 10⁻³⁴ 5 10⁻²⁵ =1.32 10⁻⁹ meter