Particle Nature of Electromagnetic Radiations

The energies  ${\mathrm{E}}_1\mathrm{and}{\mathrm{E}}_2$  of two radiations are $25 \mathrm{eV}$ and $50 \mathrm{eV}$, respectively. The relation between their wavelength i.e.,  ${\mathrm{\lambda }}_1\mathrm{and}{\mathrm{\lambda }}_2$ will be:

The value of Planck’s constant is  $6.63\times {10}^{-34}Js.$  The velocity of light is  $3.0\times {10}^{8}m{s}^{-1}.$  Which value is closest to the wavelength in meters of a quantum of light with frequency of  $8\times {10}^{16}{s}^{-1}?$

Explain the ejection of electrons from metal surface and their relation to the particle nature of electromagnetic radiations

Tell about the particle nature of electromagnetic radiation by the photoelectric effect.

Define absorption and emission spectra.

Name the phenomenon which shows the quantum nature of electromagnetic radiation. 

What is the quantum nature of electromagnetic radiation.

The amount of light emitted (intensity of radiation) from a black body and its spectral distribution depends only on its temperature.

_____ black approximates fairly closely to the black body.

What are the properties of black body?

What do you mean by the term photoelectrons?

The photoelectric effect is the emission of _____ or other free carriers when light shines on a material.

$1$ mole of photons, each of frequency $250 {\mathrm{s}}^{-1}$ would have approximately a total energy of $1 \mathrm{e}\mathrm{r}\mathrm{g}$.

In photoelectric effect, the kinetic energy of the photoelectrons increases linearly with the frequency of incident light.

The "Kangri" is an earthen pot used to stay warm in Kashmir during the winter months. Assume that the "Kangri" is spherical and of surface area $7\times {10}^{-2} {\mathrm{m}}^2.$ It contains $300 \mathrm{g}$ of a mixture of coal, wood and leaves with calorific value of $30 \mathrm{kJ} {\mathrm{g}}^{-1}$ (and provides heat with $10\%$ efficiency). The surface temperature of the 'Kangri' is $60°\mathrm{C}$ and the room temperature is $0°\mathrm{C}.$ Then, a reasonable estimate for the duration t (in hours) that the 'kangri' heat will last is (take the 'kangri' to be a black body):

A zinc ball of radius, $R=1 \mathrm{cm}$ charged to a potential $-0.5 \mathrm{V}.$ The ball is illuminated by a monochromatic ultraviolet $\left(UV\right)$ light with a wavelength $290\mathrm{nm}.$ The photoelectric threshold for zinc is $332\mathrm{nm}.$ The potential of ball after a prolonged exposure to the $UV$ is

A certain metal has a work function of $\Phi =2\mathrm{eV}$. It is irradiated first with $1 \mathrm{W}$ of $400\mathrm{nm}$ light and later with $1 \mathrm{W}$ of $800\mathrm{nm}$ light. Among the following, the correct statement is: [Given:Planck constant $\left(\mathrm{h}\right)$$=6.626\times {10}^{-34} {\mathrm{m}}^2{\mathrm{kgs}}^{-1}$ Speed of light $\left(\mathrm{c}\right)=3\times {10}^8 {\mathrm{ms}}^{-1}$]

A certain stellar body has radius $50R_s$ and temperature $2T_s$ and is at a distance of $2\times {10}^{10} \mathrm{AU}$ from the earth. Here, $\mathrm{AU}$ refers to the earth-sun distance and $R_s$ and $T_s$ refer to the sun's radius and temperature, respectively. Take, both star and sun to be ideal black bodies. The ratio of the power received on earth from the stellar body as compared to that received from the sun is close to