A monochromatic light passes through a glass slab of thickness 9cm in time t_1 IF it takes a time t_2 to travel the same distance through water . The value of (t_1-t_2) is

A monochromatic light passes through a glass slab of thickness 9cm in

1.	A monochromatic light passes through a glass slab of thickness 9cm in time t_1 IF it takes a time t_2 to travel the same distance through water . The value of (t_1-t_2) is
Answer» `5 TIMES 10^-11 SEC` `5 times 10^-8 sec` `2.5 times 10^-10 sec` `5 times 10^-10 sec` ANSWER :A