If a change in current of $0.01 ~A$ in one coil produces a change in magnetic flux of $2 \times 10^{-2} ~Wb$ in the other coil,then the mutual inductance of the two coils in henry is (in $~H$)

How can the production of dihydrogen,obtained from 'coal gasification',be increased?

If the coordinate axes are the bisectors of the angles between the pair of lines $ax^2 + 2hxy + by^2 = 0$ where $h^2 > ab$ and $a \neq b$,then

For a binomial variate $X$,if $n=4$ and $P(X=4)=6 P(X=2)$,then the value of $p$ is

If $x^2+y^2+z^2 \neq 0, \quad x=c y+b z, \quad y=a z+c x$ and $z=b x+a y$,then $a^2+b^2+c^2+2 a b c$ is equal to

The time taken for a calorimeter containing $75 \ g$ of water at $62^{\circ} C$ to cool to $58^{\circ} C$ is $9 \ \text{minutes}$. When the calorimeter contains $105 \ g$ of water, it takes $12 \ \text{minutes}$ to cool from $62^{\circ} C$ to $58^{\circ} C$. The water equivalent of the calorimeter is: (in $g$)