Recent content by Zubair Ahmad

Ok what is a line then

Same as you understood

Combination of collinear points

Are the points (1,0) and (0,1) collinear?

Is it necessary that the image of the point object placed on the axis of optical system has its image formed on the axis? Consider paraxial approximation.

Tell in a nutshell the Fermat's Principle which is applicable everywhere.

Give an example where light takes longer time

It means there is a path for which time is always minimum and on either side infinitesimally apart there are paths for which travel time is same but different from the actual path (greater than actual path)

Of what. Time or path

Is time taken by light always minimum between two points. If yes then what is wrong with Fermat's original statement?

What does superposition of SHM means physically.. I mean how is it that two shms superpose on same system?

Doesn't dr points towards center as we move test charge towards the center? Thus dr is dr(-r^)

In Griffith's electrodynamics chapter 2 example 7 he calculates potential due to a spherical shell outside it. Here E is radially outward while dr is radially inward as we are going towards the sphere hence E.dr should be negative but it is taken positive?

Yes that's clear to me.

I am not getting the way Griffith's has done. He says some charges move around. So I consider these to be some external charges. Now he uses rho and J of these external charges but when he uses Maxwell equations he relates this rho and J with E and B of older charge and current configuration...