Mutual inductance of two coils can be increased by

The pointer of a dead-beat galvanometer gives a steady deflection because

Two coaxial coils are very close to each other and their mutual inductance is $5 \,mH$. If a current $50 sin 500 \,t$ is passed in one of the coils then the peak value of induced e.m.f in the secondary coil will be ........... $V$

With the decrease of current in the primary coil from $2\,amperes$ to zero value in $0.01\,s$ the $emf$ generated in the secondary coil is $1000\,volts$. The mutual inductance of the two coils is......$H$

What is the coefficient of mutual inductance when the magnetic flux changes by $2 \times {10^{ - 2}}\,Wb$ and change in current is $0.01\,A$......$henry$

Two circuits have coefficient of mutual induction of $0.09$ $henry$. Average $e.m.f$. induced in the secondary by a change of current from $0$ to $20$ $ampere$ in $0.006$ $second$ in the primary will be......$V$