Which of the following is an incorrect match?

The potential difference between the plates of a parallel plate capacitor is changing at the rate of $10^6\, V/s$. If the capacitance is $2\,\mu F$,the displacement current in the dielectric of the capacitor will be.....$A$

Which one of the following halogens liberates oxygen,when passed through hot concentrated $KOH$ solution?

If $y=A \cos n x+B \sin n x$, then $y_2+n^2 y$ is equal to

If the centroid of the triangle formed by the lines $2y^2 + 5xy - 3x^2 = 0$ and $x + y = k$ is $\left(\frac{1}{18}, \frac{11}{18}\right)$,then the value of $k$ equals $............$

$A$ long solenoid has $200$ turns per cm and carries a current $i$. The magnetic field at its centre is $6.28 \times 10^{-2} ~Wb/m^2$. Another long solenoid has $100$ turns per cm and it carries a current $\frac{i}{3}$. The value of the magnetic field at its centre is nearly: