Embibe Experts Solutions for Chapter: Dual Nature of Matter and Radiation, Exercise 5: Exercise (Previous Year Questions)

An $\alpha -$particle moves in a circular path of radius $0.83 \mathrm{cm}$ in the presence of a magnetic field of $0.25 \mathrm{Wb} {\mathrm{m}}^{-2}$. The de Broglie wavelength associated with the particle will be:

The wavelength ${\lambda }_e$ of an electron and ${\mathrm{\lambda }}_{\mathrm{p}}$ of a photon of same energy $\mathrm{E}$ are related by:

If the kinetic energy of the particle is increased to $16$ times its previous value, the percentage change in the de-Broglie wavelength of the particle is:

When a metallic surface is illuminated with radiation of wavelength $\mathrm{\lambda }$, the stopping potential is $\mathrm{V}$. If the same surface is illuminated with radiation of wavelength $2\mathrm{\lambda }$, the stopping potential is $\frac{\mathrm{V}}{4}$. The threshold wavelength for the metallic surface is:

The de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature $T$ (kelvin) and mass $m$, is:

An electron of mass $m$ with an initial velocity $\overrightarrow{v}=v_0\hat{i}\left(v_0>0\right)$ enters an electric field $\overrightarrow{E}=-E_0\hat{i}\left(E_0=\mathrm{constant}>0\right)$ at $t=0$. If ${\lambda }_0$ is its de-Broglie wavelength at time $t=0$ then wavelength at time $t$ is:

When photon of wavelength ${\lambda }_1$ is incident on a metal surface then speed of ejected fastest electron is $v_1 \mathrm{m} {\mathrm{s}}^{-1}$. If photon of wavelength ${\mathrm{\lambda }}_2$ incident on the same metal then speed of ejected fastest electron is $v_2 \mathrm{m} {\mathrm{s}}^{-1}$. Value of $v_2^2-v_1^2$ will be:-

Electrons with de-Broglie wavelength $\lambda$ fall on the target in an X-ray tube. The cut-off wavelength of the emitted X-ray is: