Which series possesses an inferior ovary?

$A$ transverse sinusoidal wave moves along a string in the positive $x-$ direction at a speed of $10\, cm/s$. The wavelength of the wave is $0.5\, m$ and its amplitude is $10\, cm$. At a particular time $t$,the snapshot of the wave is shown in the figure. The velocity of point $P$ when its displacement is $5\, cm$ is:

Let $P(a\sec \theta, b\tan \theta)$ and $Q(a\sec \varphi, b\tan \varphi)$,where $\theta + \varphi = \frac{\pi}{2}$,be two points on the hyperbola $\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1$. If $(h, k)$ is the point of intersection of the normals at $P$ and $Q$,then $k$ is equal to

Two simple harmonic motions of angular frequency $100 \ rad \ s^{-1}$ and $1000 \ rad \ s^{-1}$ have the same displacement amplitude. The ratio of their maximum acceleration is

$A$ Zener diode,having a breakdown voltage equal to $15\,V,$ is used in a voltage regulator circuit as shown in the figure. The current through the diode is ........ $mA$.

$A$ disc of radius $R$ and thickness $\frac{R}{6}$ has moment of inertia $I$ about an axis passing through its centre and perpendicular to its plane. The disc is melted and recast into a solid sphere. The moment of inertia of the sphere about its diameter is