The wavelength of ${K_\alpha }$ line for an element of atomic number $29$ is $\lambda $ . Then the wavelength of ${K_\alpha }$ line for an element of atomic no $15$ is (Take mosley‘s constant $b = 1$ for both elements)
$\frac{{29}}{{15}}\lambda $
$\frac{{28}}{{15}}\lambda $
$4\lambda $
$2\lambda $
The following diagram indicates the energy levels of a certain atom when the system moves from $2E$ level to $E$, emitting a photon of wavelength $\lambda $. The wavelength of photon produced during its transition from $\frac{4E}{3}$ level to $E$ is
Explain Rutherford's explanation for scattered $\alpha $ -particles.
Assertion: The specific charge of positive rays is not constant.
Reason: The mass of ions varies with speed.
Match List $- I$ (Experiment performed) with List $-II$ (Phenomena discovered/associated) and select the correct option from the options given the lists
List $- I$ | List $- II$ |
$(1)$ Davisson and Genner | $(i)$ Wave nature of electrons |
$(2)$ Millikan's oil drop experiment | $(ii)$ Charge of an electron |
$(3)$ Rutherford experiment | $(iii)$ Quantisation of energy levels |
$(4)$ Franck-Hertz experiment | $(iv)$ Existence of nucleus |