Two circular loops of diameters 0.6 cm and 40 cm are kept coaxially with a separation of 15 cm between their centres . If a current 2 A flows through the smaller loop then the flux linked with the bigger loop is (approximately )

Options

A. `9xx10^(-11)` wb
B. `0.9 xx 10^(-11) Wb`
C. `1.8 xx 10^(-11) ` Wb
D. `2.7 xx 10^(-11)` Wb

Explanation

( None of the option is matching )
Magnetic field intensity due to small loop at location of larger loop is
`B_(1)=(mu_(0)Ir^(2))/(2x^(3))=(4pixx10^(-7)xx2xx(0.3xx10^(-2))^(2))/(2xx(15xx10^(-2))^(3))=(36pi)/(15^(3))xx10^(-9)T`
Flux linked with larger loop is
` phi_(2)= B_(1)A_(2)= (86pi)/(15^(3))xx10^(-19)xxpixx(20xx10^(-2))^(2)`
=` (36pi^(2))/(15^(3))xx4xx10^(-11)= 0.42xx10^(-11)` Wb