A Ray of light enters into benzene from air if the refractive index of benzene is 1.50 by what percent the speed of light reduces while entering into benzene

Dear Student
c/v_air = 1.003
c/v_ben =1.50
v_ben /v_air = 1.0003/1.50 =speed of light in air / speed of i=light in benzene
 decreasing in speed = [(v_air -v_ben) * 100 ] / v_air  = (1 - v_ben / v_air) * 100
                                  = (1-1.003/1.50)* 100
                                  =  33.37%
​​ Regards