Question

$v_o$ and $v_E$ represent the velocities, ${\mu }_o$ and ${\mu }_E$ the refractive indices of ordinary and extraordinary rays for a doubly refracting crystal. Then

• A. $v_o\ge v_E,{\mu }_o\le {\mu }_E$ if the crystal is calcite
• B. $v_o\le v_E,{\mu }_o\le {\mu }_E$ if the crystal is quartz
• C. $v_o\le v_E,{\mu }_o\ge {\mu }_E$ if the crystal is calcite
• D. $v_o\ge v_E,{\mu }_o\ge {\mu }_E$ if the crystal is quartz

Answer 1

Answer: (C)

In double refraction light rays always splits into two rays $(O$ -ray and $E$ -ray $).O$ -ray has same velocity in all direction but $E$ -ray has different velocity in different direction.
For calcite ${\mu }_e<{\mu }_0\Rightarrow v_e>v_0$
For quartz ${\mu }_e>{\mu }_0\Rightarrow v_0>v_e$