What does “Total internal reflection” actually mean in Ray Optics & Optical Instruments, and why does it matter for JEE?
past a critical angle, light going from denser to rarer medium reflects entirely instead of refracting.
In simple words: past a critical angle, light going from denser to rarer medium reflects entirely instead of refracting. Getting Total internal reflection clear matters because JEE questions on Ray Optics & Optical Instruments usually test this idea directly, not just a formula you memorised.
Key point
Total internal reflection
Common mistake
expecting TIR when light goes from rarer to denser medium.
Memory tip
TIR needs dense-to-rare travel AND an angle beyond the critical angle.
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