Question

Light can be described as a wave or as a particle known as a photon. The speed of light c is 3.00 ✕ 108 m/s. (a) Sirius is the brightest star in the night sky, 8.18 ✕ 1016 m from the Earth. Find the time it takes a photon to reach us from Sirius. Give your answer in years. (Assume one year is 365 days.)

Answer 1

Answer:

The answer is 8.64 light years.

Explanation:

The formula used for this is the light travel equations.

$d=c*t$

where d = distance light travels in one year

c  = speed of light

t = seconds in one year

now

$d=3.0*10^8 * (365*24*60*60)\\d = 9.46*10^1^2 km\\9.46*10^1^5m$

Now we have calculated the distance light covers in one year and we have distance from Sirius star to earth which is given in the statement

$distance=8.18*10^1^6m$

Dividing the distance of sirius from earth to the distance light travels in one year will give the time required for light to reach earth from Sirius .

$=8.18*10^1^6/9.46*10^1^5\\=8.64$

Therefore, it will take 8.64 light years for a photon to reach us from Sirius.