Chapter 27, Problem 69A

(a)

To determine

The amount of the wavelength of light thick the thumbnail is.

Answer to Problem 69A

The amount of the wavelength of light thick is the thumbnail is $\frac{x}{\lambda }$ .

Explanation of Solution

Given:

The wavelength of the light = $\lambda$

The thickness of the thumbnail = $x$

Calculation:

The amount of the wavelength thick the thumbnail is $\frac{x}{\lambda }$

Where, x is thickness

  $\lambda$ is wavelength of wave

Conclusion:

So, $\frac{x}{\lambda }$ is the amount of wavelength of light thick is the thumbnail.

(b)

To determine

To Calculate: The amount of the wavelengths thick the thumbnail is.

Answer to Problem 69A

The amount of the wavelengths thick the thumbnail is 800.

Explanation of Solution

Given:

The wavelength of green light, $\lambda ==500\text{ nm}$

Thickness, $x==0.40\text{ mm}$

Formula used:

The amount of the wavelength thick the thumbnail is $\frac{x}{\lambda }$ .

Where, x is thickness

  $\lambda$ is wavelength of wave

Calculation:

Firstly, convert the wavelength from nanometer to meter

  $\lambda =500\times {10}^{\text{-9}}\text{m}\left(\because 1\text{nm}={10}^{-9}\text{m}\right)$

And, thickness into the meter

  $x=0.40\times {10}^{-3}\text{m}$

So, the amount of the wavelength thick the thumbnail is

  $\begin{array}{l}\frac{x}{\lambda }=\frac{0.40\times {10}^{-3}}{500\times {10}^{-9}}\\ =\frac{40}{5}\times {10}^2\\ =800\end{array}$

Conclusion:

Thumbnail is 800 times the wavelength of green light.