1 Vitaly, November 2, 2008 at 8:38 p.m.:

Very nice lecture, recommend to anyone who wants to broad their school knowledge.

2 Kiran, January 12, 2009 at 8:50 p.m.:

Index of refraction_blue and red

Dear Sir, First of all, my sincere thanks for sharing such a beautiful class. Now I'm confident that I'll remember these concepts which are demonstrated practically by Prof Lewin. One thing I noticed, rather want to confirm my understanding, is: Professor explained using a slide that as frequency of EM wave increases, index of refraction, n decreases. However few minutes after it was mentioned that index of refraction for blue light is more (1.343) than that of red (1.331). Blue color frequency is more than that of red. Then how this can happen ? Kindly clarify.

Thank you once again for the useful presentation.

Sincerely Kiran

3 utkarsh singh, December 28, 2011 at 2:22 a.m.:

to study about mit

4 raj rai, June 20, 2014 at 4:22 p.m.:

prof.lewin i want to thank you for your activity to change the mass of the bob .

5 raj rai, June 20, 2014 at 4:22 p.m.:

prof.lewin i want to thank you for your activity to change the mass of the bob .