Question-08 Two coils P and Q are kept near each other. When no current flows through coil P and current increases in coil Q at the rate of 10\ A/s, the e.m.f. in coil P is 15\ mV. When coil Q carries no current and current of 1.8\ A flows through coil P, the magnetic flux linked with coil Q is
(A) 1.8\ mWb
(B) 2.7\ mWb
(C) 1.5\ mWb
(D) 1\ mWb
Answer : (B)
Explanation:
\phi_Q=MI_PBut,
|e_p|=M\frac{dI_Q}{dt} M=\frac{e_p\times dt}{dI_Q}∴ \phi_Q=\frac{e_p\times dt}{dI_Q}\times I_P
\phi_P=\frac{15\times10^{-3}}{10}\times1.8 \phi_P=2.7\times10^{-3}\ Wb=2.7\ mWb