Chapter 3, Problem 93A

Interpretation Introduction

Interpretation : The minutes taken by light to travel from the sun to earth are to be calculated.

Concept Introduction : Time is the dimension on which any system evolves. The object's overall path traveled during a particular period of time is its distance. The formula of time is given as:

  $\text{time}\text{=}\frac{\text{distance}}{\text{speed}}$

Answer to Problem 93A

The minutes taken by light to travel from the sun to earth is $8.33\text{min}$ .

Explanation of Solution

Given information:

The speed of light is $3\times {10}^8\text{m/s}$

The distance of the earth from the sun is $1.5\times {10}^8\text{km}$ .

It is known that $\text{1}\text{km}\text{=}{\text{10}}^3\text{m}$ and $\text{1}\text{min}\text{=}\text{60 sec}$ .

Distance is the sum of an object's movements, regardless of direction.

The formula of time is given as:

  $\text{time}\text{=}\frac{\text{distance}}{\text{speed}}$

To calculate the time traveled from the earth to the sun, substitute the values in the above formula:

  $\begin{array}{c}\text{time}\text{=}\frac{\text{distance}}{\text{speed}}\\ =\frac{1.5\times {10}^8\cancel{\text{km}}}{3\times {10}^8\cancel{\text{m}}}\times \cancel{\text{s}}\text{×}\frac{1\text{min}}{60\cancel{\text{s}}}\times \frac{{10}^3\cancel{\text{m}}}{1\cancel{\text{km}}}\\ =8.33\text{min}\end{array}$