Question

magnetism question @Mashy

Answer 1

C is the answer!

Answer 2

:D

Answer 3

okay!

Answer 4

42??

Answer 5

both.

Answer 6

this is quite simple :O.. just use Biot Savart's law :O

Answer 7

ok what i did is.
dI=J.dA where dA=2*pie*r dr. integrated and found B through amperes law.
but then i noticed there is no 'a' in the answer.

Answer 8

how will i use it here? idl*r/r^2 *mu/4pi ?

Answer 9

r^3 *

Answer 10

You have a direct formula for current due to a long straight conductor derived from ampere's circuital law..


\[B = \frac{ \mu0 }{ 4 \pi }\frac{ I }{ r }\]

all you need to know now is I.. for that we gotta use current density!

Answer 11

2I/r??

Answer 12

no no wait wait wait!!

Answer 13

also when i find I, 'a' will be there in the answer. but no option has a.

Answer 14

wait. lemme first get the answer.. and verify ok?

Answer 15

alright. should i tell you the answer? :P

Answer 16

no no wait..

Answer 17

b ?

Answer 18

CANT YOU GIVE MY EXAM? :o

Answer 19

:D.. ok lemme draw1

Answer 20

does that make sense?