Question

choose the best approximation of the number of seconds in a year. choose 1 answer: (a) 3·10^6 seconds (b) 3·10^7 seconds light travels at a rate of about 9,460,528,400,000,000 m per year. choose the best approximation of how many meters light travels per year. choose 1 answer: (a) 9·10^15 meters (b) 9·10^16 meters approximately how many meters does light travel per second? choose 1 answer: (a) 3·10^8 meters per second (b) 3·10^9 meters per second (c) 3·10^10 meters per second

Explanation:

Step1: Calculate seconds in a year

There are 365 days in a non - leap year. Each day has 24 hours, each hour has 60 minutes and each minute has 60 seconds. So the number of seconds in a year is $365\times24\times60\times60=31536000\approx3\times10^{7}$ seconds.

Step2: Approximate light - year distance

The distance light travels in a year is 9,460,528,400,000,000 m. In scientific notation, $9460528400000000 = 9.4605284\times 10^{15}\approx9\times 10^{15}$ m.

Step3: Calculate light speed per second

We know the distance light travels in a year ($d\approx9\times 10^{15}$ m) and the number of seconds in a year ($t\approx3\times 10^{7}$ s). Using the formula $v=\frac{d}{t}$, we have $v=\frac{9\times 10^{15}}{3\times 10^{7}} = 3\times 10^{8}$ m/s.

Answer:

1. B. $3\cdot 10^{7}$ seconds
2. A. $9\cdot 10^{15}$ meters
3. A. $3\cdot 10^{8}$ meters per second