Question

Light takes 8 min 20 sec to reach from sun on the earth. If the whole atmosphere is filled with water, the light will take the time (${ } _ { a } \mu _ { w } = 4 / 3$)

• A. 8 min 20 sec
• B. 8 min
• C. 6 min 11 sec
• D. 11 min 6 sec

Answer 1

Answer: (D)

11 min 6 sec

Answer 2

$\mu = \frac { c _ { a } } { c _ { w } } = \frac { t _ { w } } { t _ { a } } \Rightarrow t _ { w } = \frac { 25 } { 3 } \times \frac { 4 } { 9 } = 11 \frac { 1 } { 9 } = 11$min 6 sec