JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
The speed of light in media \('A'\) and \('B'\) are \(2.0 \times\) \(10^{10} \,cm / s\) and \(1.5 \times 10^{10} \,cm / s\) respectively. A ray of light enters from the medium \(B\) to \(A\) at an incident angle ' \(\theta\) '. If the ray suffers total internal reflection, then
- A \(\theta=\sin ^{-1}\left(\frac{3}{4}\right)\)
- B \(\theta > \sin ^{-1}\left(\frac{2}{3}\right)\)
- C \(\theta < \sin ^{-1}\left(\frac{3}{4}\right)\)
- D \(\theta > \sin ^{-1}\left(\frac{3}{4}\right)\)
Answer & Solution
Correct Answer
(D) \(\theta > \sin ^{-1}\left(\frac{3}{4}\right)\)
Step-by-step Solution
Detailed explanation
\(\sin i _{ c }=\frac{ n _{ r }}{ n _{ d }}=\frac{ C _{ d }}{ C _{ r }}=\frac{1.5 \times 10^{10}}{2 \times 10^{10}}\) \(\sin i _{ c }=\frac{3}{4}\) \(i _{ c }=\sin ^{-1}\left(\frac{3}{4}\right)\) for T I R \(\quad \theta> i _{ c }\)…
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