课间,有同学来问2008全国理综卷Ⅰ第21题。题目一束由红、蓝两单色光组成的光线从一平行玻璃砖的上表面以入射角θ射入,穿过玻璃砖自下表射出。已知该玻璃对红光的折射率为1.5。设红光与蓝光穿过玻璃砖所用的时间分别为t_1和t_2,则在θ从0°逐渐增大至90°的过程中(A)t_1始终大于t_2(B)t_1始终小于t_2(C)t_1先大于后小于t_2(D)t_1先小于后大于t_2 During class, there are classmates to ask 2008 National Science Volume Ⅰ 21 questions. A beam of light consisting of red and blue monochromatic light is incident at an angle of incidence θ from the upper surface of a parallel glass tile and emitted through the glass tile from the table below. It is known that this glass has a refractive index of 1.5 for red light. Assuming that the time taken for the red and blue light to pass through the glass brick are t_1 and t_2, respectively, θ increases from θ to 90 ° gradually (A) t_1 is always greater than t_2 (B) t_1 is always less than t_2 (C) t_1 The first is greater than the latter less than t_2 (D) t_1 first less than the latter greater than t_2