NTNUJAVA Virtual Physics Laboratory
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Easy Java Simulations (2001- ) => Questions related to EJS => Topic started by: ahmedelshfie on May 12, 2010, 01:41:03 am



Title: Physics of rainbow (EJS version)
Post by: ahmedelshfie on May 12, 2010, 01:41:03 am
This applet is Physics of rainbow (EJS version)
Created by prof Hwang modified by Ahmed
Original project Physics of rainbow (EJS version) (http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1430.0)
I'm really wonder from this simulation how much is fantastic
One word about this simulation wonderful :)  ;D


Title: Re: Physics of rainbow (EJS version)
Post by: ahmedelshfie on May 12, 2010, 01:47:26 am
You can click the "real intensity" checkbox to find out the relative intensity for different paths.
You can drag the black square near the left side of the simulation to drag those rays up and down.

You might notice that intensity for incoming rays are not the same. It is indicated that the cross section are not the same for different ray.
If the ray is off by the center of the water drop by distance b, and the rasius of the circle is R.
The incident angle $\theta$, where$ \sin\theta=b/R$, the effective cross section is proportional to $\cos\theta$

If the index of refraction is n, the refracted angle$ \phi$, where$ \sin\phi=b/R/n ( i.e. sin\theta= n \sin\phi)$.

If the intensity of incoming ray is $I$, then the intensity for the reflected ray(s wave) is $I_r=\frac{\sin^2(\theta-\phi)}{\sin^2(\theta+\phi)} I$ and the intensity for refracted light is $I$'$ =$$I-I_r$

The above formulas are used to calculate the intensity for different ray.
I hope the above simulation can help you understand more about the physics of rainbow.
You are welcomed to check out Physics of Rainbow (http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=44) for more in depth discussion about rainbow


Title: Re: Physics of rainbow (EJS version)
Post by: ahmedelshfie on May 12, 2010, 10:15:25 am
Prof Hwang please i had a problem for typing last equation like in page
Of original project can you solve it please
Thank you


Title: Re: Physics of rainbow (EJS version)
Post by: Fu-Kwun Hwang on May 12, 2010, 08:56:50 pm
This forum support TeX syntax for mathematics equation.
It is similar to wiki mathematics equation.
However, the equation is enclose between dollar signs.
Please check out for syntax http://en.wikipedia.org/wiki/Math_markup


Title: Re: Physics of rainbow (EJS version)
Post by: ahmedelshfie on May 12, 2010, 11:30:28 pm
Yes i check I'm typing equations right I'm just meet a problem in
Last symbol after $I$ direct is this only the problem but equations i typing right
I will attach image and mark what the problem for you check prof