Answer: in air 33.33 ps and in the glass 50 ps: so the difference 16.67 ps
Explanation: In order to calculate the time for a pulse travellin in air and in a glass we have to consider the expresion of the speed given by:
v= d/t v the speed in a medium is given by c/n where c and n are the speed of light and refractive index respectively.
so the time is:
t=d/v=d*n/c
in air
t=0.01 m*1/3*10^8 m/s= 33.33 ps
while for the glass
t=0.01 m*1.5* 3* 10^8 m/s= 50 ps
Finally the difference is (50-33.33)ps = 16.67 ps
