Answer :
Speed of light=3x10^8m/s
time=2ns=2x10^-9s
distance traveled=timexspeed
3x10^8 x 2 x10^-9
6x10^-1=0.6m
time=2ns=2x10^-9s
distance traveled=timexspeed
3x10^8 x 2 x10^-9
6x10^-1=0.6m