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?
Doubt by Japjee
Solution :
We know,
Speed = Distance / Time
OR
Speed = Distance / Time
OR
Distance = Speed × Time — (1)
As per the question
Speed of Light = 1 new unit of length per second
Speed of Light = 1 new unit of length per second
Time = 8 min + 20 seconds
= (8×60) + 20
= 480 + 20
= 500 sec
= (8×60) + 20
= 480 + 20
= 500 sec
Putting the values of speed and Time in equation (1)
Distance = 1×500
= 500 new units of length.
Hence, the distance between the earth and sun is 500 new units of length.