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 $6.02\times {10}^{23}$