Total flux through ' S1 ' and ' S3 ' is equal to Zero. Since, magnetic flux through a closed surface is zero. ϕS1+ϕS3=0⇒ϕS1=−ϕS3 ......(1) ϕS3=B(ϕS1)=(2×10−3)(πR2)⇒ϕS3=(2×10−3)π(
100
π
) =2×10−1 weber ∴ϕS1=−2×10−1wb Total flux through ' S3 ' and ' S2 ' is equal to zero. ϕS2+ϕ′S3=0 ⇒ϕS2=−ϕ′S3 ⇒ϕS2=−(−2×10−1)(ϕ′S3=−ϕS3) ⇒ϕS2=2×10−1 weber