Question

If it takes $8$ minutes for light to travel from the Sun to the Earth, calculate the distance between the Sun and the Earth. (speed of light $=3\times {10}^8{\text{m s}}^{-1}$)

• A. $1.44\times {10}^8\text{m}$
• B. $1.44\times {10}^8\text{km}$
• C. $24\times {10}^8\text{m}$
• D. $24\times {10}^8\text{km}$

Answer 1

The correct option is B $1.44\times {10}^8\text{km}$

Given,
Time taken by light to reach earth,
$\text{t}=8\text{minutes}=8\times 60=480\text{s}$

Speed of light,
$v_c=3\times {10}^8{\text{m s}}^{-1}$

Distance from the Sun to the Earth,
$\text{d}=v_c\times \text{t}=3\times {10}^8\times 480$
$\Rightarrow \text{d}=1440\times {10}^8\text{m}=1.44\times {10}^8\text{km}$