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A light-year is the distance travelled by light in a vacuum in one year - Leaving Cert Physics - Question a - 2019

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A light-year is the distance travelled by light in a vacuum in one year. Calculate this distance in metres.

Worked Solution & Example Answer:A light-year is the distance travelled by light in a vacuum in one year - Leaving Cert Physics - Question a - 2019

Step 1

Calculate the distance using the formula s = vt

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Answer

To calculate the distance travelled by light in one year, we can use the formula:

s=vts = vt

where:

  • ss is the distance,
  • vv is the speed of light, approximately 3.00×1083.00 \times 10^8 m/s,
  • tt is the time in seconds for one year.

Step 2

Convert time from years to seconds

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Answer

Since one year contains approximately 3.15×1073.15 \times 10^7 seconds, we can substitute this into our formula.

Step 3

Combine the values to compute the distance

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Answer

Now substituting the values into the equation:

s=(3.00×108 m/s)×(3.15×107 s)s = (3.00 \times 10^8 \text{ m/s}) \times (3.15 \times 10^7 \text{ s})

Performing the multiplication, we arrive at:

s=9.45×1015 ms = 9.45 \times 10^{15} \text{ m}

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