(a) 
The relationship between frequency and wavelength of an electromagnetic wave is given by
where
is the speed of light
is the frequency
is the wavelength
In this problem, we are considering light with wavelength of
Substituting into the equation and re-arranging it, we can find the corresponding frequency:
(b) 
The period of a wave is equal to the reciprocal of the frequency:
And using 
as we found in the previous part, we can find the period of this wave:
Explanation:
By the way.. What's the meaning of ANTISOCIAL??..(ㆁωㆁ)
If you tell me the meaning of it, I'll tell you my answer too(ㆁωㆁ)
The answer is A) variable. The depression level is a value that varies with the respondents and may inform you about the relationship between depression and other variables, such as alcohol use or sleep habits. It is also likely a discrete variable, since the answer is probably an integer (1, 2, ... 10), rather than a continuous spectrum (virtually any number between 1 and 10).
Buy a fan or heater, get a blanket, take a shower, go outside, go by the fireplace
