Height of water that would be filled in a container of height 21 cm so that it appears half filled to the observer when veiwed from the top of container is
[refractive index of water = 4/3]
1.)8 cm
2.) 10.5 cm
3.)12 cm
4.)14 cm
please explain!
Respected sir/ madam
Is mu (sign of refractive index)=Real depth/Apparent depth and
mu (sign of refractive index)=Apparent height/ Real height, sir,are these two equations correct? which one will be used for solving the above question? please tell me when to use which equation?
I am in great confusion .Please help!
 
 
 
 
 
 

Asked by Kb Aulakh | 25th Apr, 2015, 05:39: PM

Expert Answer:

Let x be the real height of water that should be filled in the container.
Then the apparent height of water as viewed from top will be (21-x), as the height of the container is given as 21 cm
 
begin mathsize 12px style We space have space that space refractive space index space of space the space medium space equals space fraction numerator Real space height over denominator Apparent space height end fraction Given space refractive space index space equals space 4 over 3 Real space height space equals space straight x Apparent space height equals space 21 space minus space straight x 4 over 3 equals fraction numerator straight x over denominator 21 minus straight x end fraction 4 open parentheses 21 minus straight x close parentheses equals 3 straight x 84 space minus space 4 straight x space equals space 3 straight x 84 space equals space 7 straight x straight x space equals 84 over 7 equals 12 space cm end style
Hence the height of the water filled in the container = 12 cm 

begin mathsize 12px style The space equation space used space to space solve space this space problem space is colon Refractive space index comma space straight mu space equals space fraction numerator Real space depth over denominator Apparent space depth end fraction space Because space light space travels space from space straight a space less space dense space medium space to space straight a space denser space medium. space straight i. straight e space air space to space water When space light space travels space from space straight a space denser space medium space to space straight a space less space denser space medium comma space then space we space take colon  Refractive space index comma space straight mu space equals space fraction numerator Apparent space depth over denominator Real space depth end fraction end style

Answered by Jyothi Nair | 27th Apr, 2015, 11:08: AM