Answer:
So the intensity of the light be smaller in second case with the polarizers at 90 degree with the vertical
Step-by-step explanation:
When two polarizers are arranged at 45 degree and 90 degree in series
so here the intensity of light coming out of the polarizers is given as
![I_1 = I_ocos^45](https://img.qammunity.org/2020/formulas/physics/college/y711prnc85n9gzq2ro8xbahics7gviviuw.png)
![I_1 = (I_0)/(2)](https://img.qammunity.org/2020/formulas/physics/college/rm1rlr1bvi84e3n1yi2cezcmawphaktz1k.png)
now for second polarizer we have
![I_2 = I_1 cos^2(90 - 45)](https://img.qammunity.org/2020/formulas/physics/college/qz2ptlg3ht6glvb33jdws723xr0b9u0czy.png)
![I_2 = ((I_0)/(2))(1)/(2)](https://img.qammunity.org/2020/formulas/physics/college/ujun6d8nhphi4exlhc8q9gnr7p142m07qf.png)
![I_2 = (I_0)/(4)](https://img.qammunity.org/2020/formulas/physics/college/bu6j7f8nuh3gn8i56029ubqxrly4i14fq0.png)
now in other case when two polarizers are inclined 90 degree to the vertical
![I = I_ocos^290 = 0](https://img.qammunity.org/2020/formulas/physics/college/905jcguf48j11wfea4fsukqckj1t4bmnqq.png)
so final intensity in second case will be ZERO
So the intensity of the light be smaller in second case with the polarizers at 90 degree with the vertical