Question

1. choose the best answer.

calculate about how many minutes it takes light from the sun to reach mars if mars is 320 million km away. (use the formula from the lesson.)
18 min
31 min
3 min
11 min

Explanation:

Step1: Recall the speed of light

The speed of light \( c = 3\times10^{5}\space km/s \) (approximate value in vacuum). The distance \( d = 320\times10^{6}\space km \). We use the formula \( t=\frac{d}{c} \) to find the time in seconds first.

$$ t=\frac{320\times 10^{6}}{3\times 10^{5}} $$

Step2: Calculate time in seconds

Simplify the fraction: \( \frac{320\times 10^{6}}{3\times 10^{5}}=\frac{3200}{3}\approx 1066.67\space s \)

Step3: Convert seconds to minutes

Since \( 1\space min = 60\space s \), divide the time in seconds by 60: \( t=\frac{1066.67}{60}\approx 17.78\space min\approx 18\space min \)

Answer:

18 min (corresponding to the option with "18 min")