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 `10 A//s`, the emf 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 the coil Q is

Options

A. `1.4 m Wb`
B. `2.2 mWb`
C. `2.7 m Wb`
D. `2.9 m Wb`

Answer

C

Explanation

Given, `(dl_(theta))/(dt) = 10A//s`
`e_(p) = 15 mA`
`= 15 xx 10^(-3)V, I_(p) = 18A`
Induced emt in coil P is given as,
`|e_(p)| = M. (dl_(Q))/(dt)`
Substituting the given values, we get
`15 xx 10^(-3) = M xx 10`
`rArr M = 15 xx 10^(-4) H`
Magnetic fluxed linked with coil Q is given as,
`phi_(Q) = MI_(p) = 15 xx 10^(-4) xx 1.8`
`= 27.0 xx 10^(-4)`
`= 2.7 xx 10^(-3) = 2.7 mWb`