CBSE 2024 · Region 1 · Set 1 · Q18 · 2 marks

Monochromatic light of frequency $\displaystyle 5.0 \times 10^{14} \mathrm{~Hz}$ passes from air into a medium of refractive index $\displaystyle 1 \cdot 5$. Find the wavelength of the light (i) reflected, and (ii) refracted at the interface of the two media.

Ray Optics and Optical InstrumentsRefractionApplyvery_short_answermedium

\begin{itemize} \item[(i)] \[ \begin{aligned}	v=v \lambda
	3 \times 10^{8}=5 \times 10^{14} \times \lambda
	\lambda=600 \mathrm{~nm} \text { or } 6 \times 10^{-7} \mathrm{~m} \end{aligned} \] \item[(ii)] \[ \begin{aligned} \lambda_{\text {medium }}	=\frac{\lambda_{\text {air }}}{\mu}
\lambda_{\text {medium }}	=\frac{600 \mathrm{~nm}}{1.5}
	=400 \mathrm{~nm} \text { or } 4 \times 10^{-7} \mathrm{~m} \end{aligned} \] OR \item[(b)] \begin{tabular}[t]{\|l\|l\|} Calculating the radius of the curved surface	$\displaystyle 2$

Marking-scheme solution