The star Betelgeuse is 6.1 x 10^18 m away from Earth. How old is the light we see from that star when it reaches us? There are 3.2 x 10^7 se

Question

The star Betelgeuse is 6.1 x 10^18 m away from Earth. How old is the light we see from that star when it reaches us? There are 3.2 x 10^7 seconds in a year (1 point)

635 years old

481 years old

727 years old

559 years old

in progress 0
Bơ 4 years 2021-08-24T12:39:17+00:00 1 Answers 15 views 0

Answers ( )

  1. thuthao
    0
    2021-08-24T12:40:59+00:00
    Reply

    Answer:

    635 years old

    Explanation:

    The light reaching the earth from the sun will travel at a speed called the speed of light, and this has a universal value of 3 × 10⁸ m/s. Bearing this in mind, let us calculate the age of the light reaching the Earth from the sun:

    Distance of star from Earth = 6.1 × 10⁸m

    Speed of light = 3 × 10⁸ m/s

    We have distance and speed, let us calculate the time of travel of the light from the star to the earth.

    Distance = speed × time

    6.1 × 10⁸ = 3 × 10⁸ × time

    time = \frac{6.1 \times 10^{18}}{3 \times 10^8}

    In order to do the division above, we will divide the whole numbers normally, then we will apply the law of indices to the power that says:

    Xᵃ ÷ Xᵇ = X⁽ᵃ⁻ᵇ⁾

    \therefore time = \frac{6.1 \times 10^{18}}{3 \times 10^8}\\= \frac{2.03 \times 10^{(18-8)}}{1} \\= 2.03 \times 10^{10}}\ seconds

    Next, we are told that there are 3.2 × 10⁷ seconds in a year.

    ∴ The number of years travelled by the light from the star:

    3.2\ \times 10^7\ seconds = 1\ year\\1\ second = \frac{1}{3.2\ \times 10^7} \\\therefore 2.03 \times 10^{10}\ seconds = \frac{2.03 \times 10^{10}}{3.2\ \times 10^7}

    please note that:

    2.03 × 10¹⁰ = 20300000000

    3.2 × 10⁷ = 32000000

    \therefore \frac{2.03 \times 10^{10}}{3.2\ \times 10^7}\\= \frac{20300000000}{32000000} \\\\= \frac{20300}{32} \\= 634.347\ years\\

    The closest answer in the option is 635 years, and we are short of this by some points due probably to approximations in the calculation.

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )