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 1

GiVeN :-

The speed of light in vacuum is unity.

To FiNd :-

The distance between the Sun and the Earth.

SoLuTiOn :-

We know,

Distance = speed × time

• Speed in unity = 1 unit /sec

• Time = 8 min and 20 secs   = (8 × 60) + 20 sec = 500 secs

Substituting the values :-

Distance between Sun and Earth = 1 × 500 = 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.