I found an answer from www.britannica.com

optics | History, Applications, & Facts | Britannica

Optics, science concerned with the genesis and propagation of **light** and with the
... in all directions at the **speed** of **light**, each **new** wave being merely the
envelope ... image **separation** at the focal **length** of the objective, the **light**-
gathering lens. ... and 6563 angstroms (the angstrom **unit**, abbreviated Å, is 10^{−}
^{8} centimetre), ...

For more information, see optics | History, Applications, & Facts | Britannica

I found an answer from www.homeschoolmath.net

**Speed**, **Time**, and **Distance Problems** Worksheet Generator

Easy **speed**, **time**, and **distance** worksheet 1: How far can it go or how long does
the trip take - using whole or half ... **Find** the average **speed**: **time** is **given** to the
fourth of an hour. ... **Find** the average **speed**: **problems** involve **conversion** of a
**time unit** ... **Time units**. Express **time** in hours and minutes. fifteen-minute
increments

For more information, see **Speed**, **Time**, and **Distance Problems** Worksheet Generator

I found an answer from www.quora.com

The metre is defined as the **distance** travelled by **light** in 1 ...

**Speed** of **light** itself is reprsented using **units** - metre/sec…then how we can
define metre ... Why didn't people choose some easier number **such** as 1/
300,000,000 ... **If** we **take** the **speed** of **light** to be 300,000,000 m/**s**, and use it to
define a metre ... This is approximately the **distance between** the **earth** and moon
and is hence, ...

For more information, see The metre is defined as the **distance** travelled by **light** in 1 ...

I found an answer from en.wikipedia.org

List of unusual **units** of measurement - Wikipedia

This standard made the historical metre 0.0197% longer than the modern
standard metre, which is calculated based on the **distance** covered by **light** in a
**vacuum** ...

For more information, see List of unusual **units** of measurement - Wikipedia

Given that

Speed of the light in vacuum is unity = 1 units/second

Time taken by the light t=8\min\ 20s

= 8 * 60 + 20 = 500 seconds

Step 1: Finding the distance between the sun and earth

Formula: \text{ Speed } = \frac{\text{ Distance }}{\text{ time }}

\text{ Distance } = \text{ Speed * time }

\text{ Distance } = 1 \text{ units/sec } * 500 sec

\text{ Distance } = 500 units

Hence, distance between the sun and earth 500 units