Chapter 23, Problem 80GP

To determine

The length of wave trains in space.

Answer to Problem 80GP

Solution:

3m

Explanation of Solution

Light travels at a speed of $c\left({\text{3×10}}^{\text{8}}\text{m/s}\right)$ Time duration of emitted light in wave-train bursts is given about ${10}^{-8}\text{s}$.

Given:

Time duration for emitted light in wave train bursts $\Delta t={10}^{-8}\text{s}$

Formula used:

$D=V\times \left(t_f-t_i\right)$ where D is distance, V is speed in this case speed will be speed of light $c$$,t_f\text{and}{t}_i$ are time initial and time final for wave bursts.

So it can be rewrite as

$D=c\times \Delta t$

Calculation:

So, the length of wave bursts in space = $c\times \Delta t$

$\begin{array}{l}D=\left({\text{3×10}}^{\text{8}}\right){\text{ m/s × 10}}^{\text{-8}}\text{s}\\ D=\text{ 3 m}\end{array}$