Question

A certain type of laser emits light that has a frequency of 4.2 × 1014 Hz. The light, however, occurs as a series of short pulses, each lasting for a time of 3.2 × 10-11 s. (a) What is the wavelength of this light? (b) How many wavelengths are there in one pulse?

Answer 1

Step-by-step explanation:

It is given that,

Frequency of the laser light,
`f=4.2* 10^(14)\ Hz`

Time,
`t=3.2* 10^(-11)\ s`

(a) Let
`\lambda` is the wavelength of this light. It can be calculated as :

`\lambda=(c)/(f)`

`\lambda=(3* 10^8)/(4.2* 10^(14))`

`\lambda=7.14* 10^(-7)\ m`

or

`\lambda=714\ nm`

(b) Let n is the number of the wavelengths in one pulse. It can be calculated as :

`n=f* t`

`n=4.2* 10^(14)* 3.2* 10^(-11)`

n = 13440

Hence, this is the required solution.