Question

A carbon-dioxide laser emits infrared light with a wavelength of 10.6 μm. What is the length of a tube that will oscillate in the m = 160000 mode? Imagine a pulse of light bouncing back and forth between the ends of the tube. How many round trips will the pulse make in each second?

Answer 1

The length of a tube and number of rounds are 0.848 m and
`1.77*10^(8)\ trip\ per\ second`.

Step-by-step explanation:

Given that,

Wavelength
`\lambda= 10.6\mu m`

m = 160000

We need to calculate the length

Using formula of wavelength

Laser tube behave like closed pipe

`m(\lambda)/(2)=L`

`L=160000*(10.6*10^(-6))/(2)`

`L=0.848\ m`

Distance traveled by pulse of light in one back and fourth trip

`d=2L`

`d=2*0.848`

`d=1.696\ m`

We need to calculate the time

Using formula for time

`t = (d)/(c)`

`t=(1.696)/(3*10^(8))`

`t=5.653*10^(-9)\ s`

We need to calculate the number of round

Using formula of number of round

`N=(1)/(t)`

`N= (1)/(5.653*10^(-9))`

`N=1.77*10^(8)\ trip\ per\ second`

Hence, The length of a tube and number of rounds are 0.848 m and
`1.77*10^(8)\ trip\ per\ second`.