Recent content by question2004

I have one question to trouble you. Why some semiconductors have a direct bandgap, while some have an indirect bandgap? Is there any very crude "thumb rule" of predicting/justifying it? Thanks a lot

I have a problem from Griffiths Introduction to EM [problem2.26] A conical surface (an empty ice-cream cone) carries a uniform surface charge <sigma>. The height of the cone is h, and the radius of the top is R. Find the potential difference between points a(the vertex) and b (the center of...

The problem is A conical surface (an empty ice-cream cone) carries a uniform surface charge <sigma>. The height of the cone is h, and the radius of the top is R. Find the potential difference between points a(the vertex) and b (the center of the top) Thanks a lot.

Hi, there, Could you please show me the solution to Griffiths Introduction to Electrodynamics, problem 2.26? The integral is so complicated. Thanks