Flux numerical

Your first doubt is about infinitesimal area element, i.e is area element in terms of d(theta) and d(phi). i will attach picture about mathematical derivation of it . 2nd doubt is ...

see attached file it's very helpful for you dear and go through the concept of spherical coordinates stystm....best regards

Important - here i am attaching derivation of area element which trouble you. in last step i multiple cos(theta) because i take dot product between E.F and area element. Hope it he...

see attached

dear....we have to add one extra term which if cos thitha due to direction convection and from geometry

In your derivation you didn't mention the cos(theta) explicitly, but you consider it Directly in area element, that's what create all fuss. Remember flux has to be normal to the su...