The sun is 1.5 × 108 km from earth. the index of refraction for water is 1.349. how much longer would it take light from the sun to reach earth if the space between them were filled with water rather than a vacuum?

175s

Explanation:

time it takes sunlight to reach the earth in  vacuum

C=light speed=299792458m/s

X=1.5x10^8km=1.5x10^11m

c=X/t

T1=X/c

T1=1.5X10^11/299792458=500.34s

time it takes sunlight to reach the earth in  water:

First we calculate the speed of light in water taking into account the refractive index

Cw=299792458m/s/1.349=222233104.5m/s

T2=1.5x10^11/222233104.5m/s=675s

additional time it would take for the light to reach the earth

ΔT=T2-T1=675-500=175s