Silliness personified #4

The colours in white light are V I B G Y O R.
Even though the colour in the middle is green, why do we take yellow to represent λavg and μavg of light? I'm really [7][7][7] and [2][2][2].

Pls tell me if You can't understand the question.

10 Answers

11
Anirudh Narayanan ·

[7][7][7][7][7][7][7]

NO REPLIES???????

[2][2][2][2][2][2][2]

62
Lokesh Verma ·

this is easy dude... see dont get biased.. there are not 7 colors but too many of them..

lamda average is (most probably) found by taking average energy..

11
Anirudh Narayanan ·

So all colours are not found in equal measure?

62
Lokesh Verma ·

it is not about equal measure..

it is like u are finding the median not the mean..

is the mean equal to the median always.. (if u remember the difference between the two from class x or ix !)

See for the data

(1,1,1,1,1,1,1,2) median is 1 but mean is 9/8

11
Anirudh Narayanan ·

Ok. Got it bhaiya. Thanx for helping [1]

I always keep getting silly doubts like this [2]

9
Celestine preetham ·

thats bcos yellow is in centre of visible spectrum

if u observe carefully , red ,orang yellow are thicker bands than blue and oth
so these 3 of em dominate half of vis spec though they r 3 in no

1
Shreyan ·

well, nishant bhaiya...how do we (or scientists) decide when to use mean and when median????
i mean..we cud have taken mean too....
and i'm also equally satisfied wid celestine's reply....

62
Lokesh Verma ·

average is by taking mean..

when we talk about taking average it means about mean...

what celestine is saying is also correct..

and here in this case it is a combination of 2...

if we were to find the "median" wavelength.. we would have taken highest+lowerst by 2.

1
Shreyan ·

http://en.wikipedia.org/wiki/File:Linear_visible_spectrum.svg
(image link....dunno why i cudnt upload it...)

well...i don't know exactly how we calculate λavg (i'm in 11th)..
but if we do like this:
visible range = 380nm to 750nm
λavg = (380 + 750)/2 = 565nm
which is close to yellow, but inside the green boundary...

and if we calculate the mean of the average wavelengths of each colour, λavg = 548nm
which is more inside green........

(cudn't guess how we'll calculate median...)

1
Shreyan ·

plz reply...am i correct???
avg does come out to be green...(although, it is quite close to yellow)

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