A star is 8.1 × 1013 km away from the earth. Suppose light travels at the speed of 3.0 × 105 km per second. How long will it take the light from the star to reach the earth ?
A. 7.5 × 103 hours
B. 7.5 × 104 hours
C. 2.7 × 1010 seconds
D. 2.7 × 1011 seconds
Answer: Option B
Solution(By Examveda Team)
Required time :$$\eqalign{ & = \left( {\frac{{8.1 \times {{10}^{13}}}}{{3.0 \times {{10}^5}}}} \right){\text{seconds}} \cr & = 2.7 \times {10^8}{\text{ seconds}} \cr & = \left( {\frac{{2.7 \times {{10}^8}}}{{60 \times 60}}} \right){\text{hours}} \cr & = 7.5 \times {10^4}{\text{ hours}} \cr} $$
Related Questions on Speed Time and Distance
A. 48 min.
B. 60 min.
C. 42 min.
D. 62 min.
E. 66 min.
A. 262.4 km
B. 260 km
C. 283.33 km
D. 275 km
E. None of these
A. 4 hours
B. 4 hours 30 min.
C. 4 hours 45 min.
D. 5 hours
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