Question

Helppp me please !!

Answer 1

the frequency of this light is
`1.5\,\,10^(16)` Hz (which coincides with the fourth option listed among possible answers)

Step-by-step explanation:

Recall the relationship between wavelength and frequency of radiation based upon the speed of light in vacuum:

`frequency\,*\,wavelength\,=\, speed\,\,of\,light\\frequency\,*\,wavelength\,=\,3\,\,10^8\,(m)/(s) \\frequency\,*\,20 \,\,10^(-9)\,m\,=\,3\,\,10^8\,(m)/(s)\\frequency\, =\,(3\,\,10^8)/(2\,\,10^(-9)) \,(1)/(s) \\frequency\,=1.5\,\,10^(16)\,\,Hz`

In the process shown above, we have written the speed of light in meters per second, and also converted the 20 nano-meters into meters, in order to reduce SI units properly and have the result shown in units of 1/second (that is hertz's - abbreviate "Hz")