The speed of light in vacuum is defined as unity in a new system of units. If sunlight takes 6 min 40 s to reach Earth, what is the Sun–Earth distance in the new length unit?
Options

Question

The speed of light in vacuum is defined as unity in a new system of units. If sunlight takes 6 min 40 s to reach Earth, what is the Sun–Earth distance in the new length unit?

G1 Physics · Accepted Answer

Step 1: Travel time t = 6 × 60 + 40 = 400 s. Step 2: Distance is d = speed × time. Step 3: With c = 1 length unit per second, d = 1 × 400 = 400 length units. Final answer: 400 (Option D).