A certain dye absorbs $4530 \mathrm{A}°$ and fluoresence at $5080 \mathrm{A}°$ . These being wavelengths of maximum absorption that under given conditions $47\%$ of the absorbed energy is emitted. Calculate the ratio of the no. of quanta emitted to the number absorbed. Round off up to three decimal places.

Iodine molecule dissociates into atoms after absorbing light of $4500{ \mathrm{A}}^0$. If one quantum of radiation is absorbed by each molecule, if $\mathrm{K}.\mathrm{E}.$ of iodine atoms is $\mathrm{y}\times {10}^{-20} \mathrm{J}.$ Then find value of $\mathrm{y}.$

(Bond energy of ${\mathrm{I}}_2=240 \mathrm{kJ}/\mathrm{mol}$ )

Suppose ${10}^{-17} \mathrm{J}$ of light energy is needed by the interior of the human eye to see an object. How many photons of green light $\left(\mathrm{\lambda }=550 \mathrm{nm}\right)$ are needed to generate this minimum amount of energy?

Given :$\frac{\mathrm{hc}}{\mathrm{\lambda }}=\frac{{\displaystyle 1240}}{{\displaystyle \mathrm{\lambda } \mathrm{in} \mathrm{nm}}}$

${10}^{\mathrm{x}}$ number of photons of radiation of frequency $5\times {10}^{13}{ \mathrm{s}}^{-1}$ that must be absorbed in order to melt one $\mathrm{g}$ ice when the latent heat of fusion of ice is $330 \mathrm{J}/\mathrm{g}.$ Find value of $\mathrm{x}.$

Use: Planck's constant $=6.626\times {10}^{-34}\mathrm{Js}$

If threshold frequency of metal is $4.5\times {10}^{\mathrm{x}}{\sec }^{-1}$ and binding energy is $180.69 \mathrm{kJ}{ \mathrm{mol}}^{-1}$ of electron. Then find value of $\mathrm{x}$.

Use: Planck's constant $=6.626\times {10}^{-34}\mathrm{Js}$

Calculate the binding energy per mole when threshold wavelength of photon is $240 \mathrm{nm}.$

Use: Planck's constant $=6.626\times {10}^{-34}\mathrm{Js}$

Round off your answer to the nearest integer.

The reaction between ${\mathrm{H}}_2$ and ${\mathrm{Br}}_2$ to form $\mathrm{HBr}$ in presence of light is initiated by the photo decomposition of ${\mathrm{Br}}_2$ into free $\mathrm{Br}$ atoms (free radicals) by absorption of light. The bond dissociation energy of ${\mathrm{Br}}_2$ is $192 \mathrm{kJ}/\mathrm{mole}.$ If the longest wavelength of the photon that would initiate the reaction is $\mathrm{y}\stackrel{\circ }{\mathrm{A}}.$ Then find value of $\mathrm{y}.$

Use: Planck's constant$=6.62\times {10}^{-34}\mathrm{Js}$ and Avogadro's number $=6.02\times {10}^{23}$

The quantum yield for decomposition of $\mathrm{HI}$ is $0.2.$ In an experiment $0.01$ moles of HI are decomposed. If the number of photons absorbed is $3\times {10}^{\mathrm{x}}.$ Then find value of $\mathrm{x}.$

Use : Avogadro's number $6.02\times {10}^{23}$