Umakant Kondapure, Collin Fernandes, Nipun Bhatia, Vikram Bathula and, Ketki Deshpande Solutions for Chapter: Electrons and Photons, Exercise 4: Evaluation Test

Radiation of wavelength $120 \mathrm{nm}$ ejects photoelectrons from a plate whose work function is $3.0 \mathrm{eV}.$ If a magnetic field of flux density $4.0\times {10}^{-5} \mathrm{T}$ is applied parallel to the plate, then the radius of the path followed by electrons ejected normally from the plate with maximum energy will be

Assertion: Work function of a metal is proportional to maximum wavelength of the photons incident.

Reason: Work function is given by the relation, ${\varphi }_0=\frac{hc}{{\lambda }_{\text{max}}}$.

In a photo electric experiment for having zero photoelectron current, the value of retarding potential
 

A proton and an $\alpha$ -particle are accelerated through the same potential difference. The ratio of de-Broglie wavelength of the proton to that of the $\alpha$ particle will be
 

Light of wavelength $3000 \stackrel{\circ }{\mathrm{A}}$ falls on sensitive surface. If the surface has received ${10}^{-7} \mathrm{J}$ of energy, then number of photons just falling on the surface are

The work function for aluminium is $4.125 \mathrm{eV}.$ The cut-off wavelength for photoelectric effect for aluminium is

Lights of two different frequencies whose photons have energies $1 \mathrm{eV}\text{ and} 2.5 \mathrm{eV}$, respectively illuminate successively a metal surface whose work function is $0.6\mathrm{eV}$. The ratio of the maximum speeds of the emitted electrons will be
 

A metallic surface is illuminated by a monochromatic light of wavelength $\lambda$. The potential difference required to stop the ejection of electrons is $3{\mathrm{V}}_0$. When the same surface is illuminated by the light of wavelength $2\lambda ,$ ${\mathrm{V}}_0$. Then for emission of photoelectrons, the threshold wavelength for the metal surface will be