A square metallic framee is made of 4 rods of same length 'a ' made of same material but rods, 1 and 2 are of thickness '2d ' & 3, 4 are of thickness d. If they are arranged as shown. Find the net magnetic induction at the point O .

Explanation

`R=(pl)/A,Rprop1/(r^(2))`
`R_(1)=R_(2)=R/4`, `R_(3)=R_(4)=R`
`I_(1)=(2RI)/((R/2)+2R)=4/5I,I_(2)=1/5I`
`bar(B_(1))=bar(B_(2))=(mu_(0))/(4pi)(4I//5)/(a//2)sqrt2,bar(B_(3))=bar(B_(4))=(mu_(0))/(4pi)(I//5)/(a//2)sqrt2odot`
`vecB_("net")=(mu_(0))/(4pi)(12sqrt2I)/(5a)`