One of the nearest stars is Alpha Centauri,whose distance is .The time it takes light to travel from Alpha Centauri to us is
A) 1.25 seconds.
B) 8.3 minutes.
C) 4.4 years.
D) 600 years.

Question

One of the nearest stars is Alpha Centauri,whose distance is  .The time it takes light to travel from Alpha Centauri to us is
A) 1.25 seconds. 
B) 8.3 minutes. 
C) 4.4 years. 
D) 600 years.

Quizplus · Accepted Answer

The distance of Alpha Centauri given in scientific notation is 4.37 × 10¹³ kilometers. The speed of light is approximately 3 × 10⁸ meters per second. We need to convert kilometers to meters by multiplying by 1000. Thus, the distance is 4.37 × 10¹⁶ meters. To find the time it takes light to travel this distance, we divide the distance by the speed of light: 
(4.37 × 10¹⁶ meters) ÷ (3 × 10⁸ meters per second) = 1.46 × 10⁸ seconds
To express this time in years, we divide by the number of seconds in a year:
1.46 × 10⁸ seconds ÷ (60 seconds per minute × 60 minutes per hour × 24 hours per day × 365 days per year) = 4.37 years (rounded to two decimal places)
Therefore, the correct answer is C, 4.4 years (rounded to one significant figure).

One of the Nearest Stars Is Alpha Centauri,whose Distance Is