A transparent cube of side d, made of a material of refractive index μ2, is immersed in a liquid of refractive index μ1 (μ1 < μ2). A ray is incident on the face AB at an angle θ (shown in the figure). Total internal reflection takes place at point E on the face BC.Then θ must satisfy:

• A. \({\rm{\theta }} < {\rm{si}}{{\rm{n}}^{ - 1}}\frac{{{{\rm{\mu }}_1}}}{{{{\rm{\mu }}_2}}}\)
• B. \({\rm{\theta }} > {\rm{si}}{{\rm{n}}^{ - 1}}\sqrt {\frac{{{\rm{\mu }}_2^2}}{{{\rm{\mu }}_1^2}} - 1} \)
• C. \({\rm{\theta }} < {\rm{si}}{{\rm{n}}^{ - 1}}\sqrt {\frac{{{\rm{\mu }}_2^2}}{{{\rm{\mu }}_1^2}} - 1} \)
• D. \({\rm{\theta }} > {\rm{si}}{{\rm{n}}^{ - 1}}\frac{{{{\rm{\mu }}_1}}}{{{{\rm{\mu }}_2}}}\)