K K Sharma Solutions for Chapter: Dual Nature of Radiation and Matter, Exercise 1: TOPICWISE QUESTIONS

Ultraviolet light of wavelength $300 \mathrm{nm}$ and intensity $1.0 \mathrm{watt} {\mathrm{m}}^{-2}$ falls on the surface of a photosensitive material. If $1\%$ of the incident photons produce photoelectrons, then the number of photoelectrons emitted from an area of $1.0 {\mathrm{cm}}^2$ of the surface is nearly

A sensor is exposed for time $t$ to a lamp of power $P$ placed at a distance $l$. The sensor has an opening that is $4d$ in diameter. Assuming all energy of the lamp is given off as light, the number of photons entering the sensor, if the wavelength of light $\mathit{\text{λ}}$ is (here $h$ is Planck's constant and $c$ is speed of light),

A photosensitive metallic surface has a work function $h{\nu }_0$. If photons of energy $2h{\nu }_0$ falls on this surface, the electrons come out with a maximum velocity of $4\times {10}^6 \mathrm{m} {\mathrm{s}}^{-1}$. When the photon energy is increased to $5h{\nu }_0$, then the maximum velocity of photoelectron will be

$1.5 \mathrm{mW}$ of $400 \mathrm{nm}$ light is directed at a photoelectric cell. If $0.1\%$ of the incident photons produces photoelectrons, the current in the cell is

If the average kinetic energy of matter waves is $kT$, then the wavelength of de Broglie waves associated with neutrons at room temperature $\mathrm{T}$ is:

The energy of a neutron of de Broglie wavelength $1\stackrel{\circ }{ \mathrm{A}}$ will be: 

The de-Broglie wavelength of a particle is same as the wavelength of a photon. Then the photon's energy is

The energy that should be added to an electron to reduce its de-Broglie wavelength from ${10}^{- 10} \mathrm{m}$to $0.5 \times {10}^{-10} \mathrm{m}$ will be