Identify the correct statement (s)

Options

A. Wavelength associated with a `1 kg` ball moving with the velocity `100 m//s` can't be calculated.
B. Wave nature of the running train is difficult to observe because wavelength is extermely small.
C. Wavelength associated with the electron can be calculated using the formulae `E=(hc)/(lambda)`
D. If an electron is accelerated through `20 V` potential difference if it has already `5eV` kinetic energy then wavelgnth of the electron is approximately `sqrt(6) Å`.

Answer

B, D

Explanation

(A) `lambda` can be calculated as : `lambda=h/(mv)=(6.626xx10^(-34))/(1xx100)=6.626xx10^(-36) m`. (very small).
(B) de-Broglie wavelength associated with macroscopic particles is extremely small and so, difficult to observe.
(C) de-Broglie wavelength associated with electron can calculated by using `lambda=h/(mv)`.
(D) `KE_(f)=5+20=25 eV :. lambda=sqrt(150/(KE_(f)))=sqrt(150/25)=sqrt(6) Å`