Which of the following is an incorrect pair?

The pressure and density of a diatomic gas $\left(\gamma = \frac{7}{5}\right)$ change adiabatically from $(P, d)$ to $(P^{\prime}, d^{\prime})$. If $\frac{d^{\prime}}{d} = 32$,then $\frac{P^{\prime}}{P}$ is

$A$ total charge $Q$ is broken into two parts $Q_1$ and $Q_2$ and they are placed at a distance $R$ from each other. The maximum force of repulsion between them will occur when:

The minimum value of the function $f(x) = x \log x$ is

$A$ particle of mass $M$ at rest decays into two particles of masses $m_1$ and $m_2$ having non-zero velocities. The ratio of the de-Broglie wavelengths of the particles,$\lambda_1/\lambda_2$ is

If the transverse and conjugate axes of a hyperbola are equal,then its eccentricity is