Discussion Forum



1)

A circular loop of radius n0.3 lies parallel to a much bigger circular loop of radius 20 cm. The centre of the smaller radius 20 cm. The centre of the smaller loop on the axis of the bigger loop. The distance between their centres is 15 cm. If a current of 2.0 A flows through the bigger loop, then the flux  linked with smaller loop is 


A) $9.1\times 10^{-11}$Wb

B) $6 \times 10^{-11}$Wb

C) $3.3\times 10^{-11}$Wb

D) $6.6 \times 10^{-11}$Wb

Answer:

Option A

Explanation:

magnetic field at  the centre of smaller loop 

      $B= \frac{\mu_{0}iR_2^2}{2(R_2^2+x^{2})^{3/2}}$

 Area  of smaller loop   $S=\pi R_1^2$

 $\therefore$  Flux  through smaller loop Φ  = BS

 Substituting the values we get, 

$\phi= 9.1\times 10^{-11}Wb$