Exercise 1.5

Transcript

Exercise 1.5 A new unit of length is chosen such that the speed of light in vacuum is unity. What is the distance between the Sun and the Earth in terms of the new unit if light takes 8 min and 20 s to cover this distance ? Let the new length unit be 𝑳^(′) And, unit of time will be the same, i.e. seconds Given that Speed of light in vacuum is unity in this new unit of length Thus, Speed of light = 𝒄=𝟏 𝑳^(′)/𝒔 We need to find distance light travels in 8 min, 20 seconds Since unit of time is in seconds, writing total time in seconds Total time = t = 8 min + 20 s = 8 × 60 + 20 = 480 + 20 = 500 s Now, Distance between sun and earth = Speed of light × Time taken = 1𝐿^(′)/𝑠×500 s = 𝟓𝟎𝟎𝑳^(′)