Question

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?
3​

Answer 1

Answer:

Distance between the Sun and the Earth = Speed of light × Time taken by light to cover the distance. Hence, Distance between the Sun and the Earth is 500 units.

Answer 2

Question:-

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 20s to cover this distance.

Answer:-

Speed of light = 1 new unit ,

Time taken = 8 min + 20s

‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎= 480s + 20s

‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎= 500s

Now,

‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎D = S/T

‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎ ‎S*T = D

‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎1 new unit/sec * 500s = D

‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎‎‎‎ ‎ ‎ ‎ ‎ ‎D = 500 new unit

Therefore, 500 new unit it will cover.