Which of the following is a fiber-yielding plant?

$A$ simple pendulum is executing simple harmonic motion with a time period $T$. If the length of the pendulum is increased by $21\%$,the percentage increase in the time period of the pendulum of increased length is ..... $\%$

If $x=a\left\{\cos \theta+\log \tan \left(\frac{\theta}{2}\right)\right\}$ and $y=a \sin \theta$,then $\frac{d y}{d x}$ is equal to

The sum of the magnitudes of two forces acting at a point is $16 ~N$. If their resultant is normal to the smaller force and has a magnitude of $8 ~N$,then the forces are:

The electrode potentials for $Cu^{2+}_{(aq)} + e^- \to Cu^{+}_{(aq)}$ and $Cu^{+}_{(aq)} + e^- \to Cu_{(s)}$ are $+0.15 \ V$ and $+0.50 \ V$ respectively. The value of $E^\circ$ for the reaction $Cu^{2+}_{(aq)} + 2e^- \to Cu_{(s)}$ will be ............ $V$.

$A$ metal sphere of radius $r$ and specific heat $S$ is rotated about an axis passing through its centre at a speed of $n$ rotations per second. It is suddenly stopped and $50 \%$ of its energy is used in increasing its temperature. Then,the rise in temperature of the sphere is