$A$ ball at rest is dropped from a height of $12 ~m$. It loses $25 \%$ of its kinetic energy on striking the ground and bounces back to a height '$h$'. Then the value of '$h$' is: (in $~m$)

Arbor vitae is composed of

$A$ photon of energy $8\,eV$ is incident on a metal surface of threshold frequency $1.6 \times 10^{15}\,Hz$. The maximum kinetic energy of the emitted photoelectrons is ...............$eV$ $(h = 6.6 \times 10^{-34}\,Js)$.

Molasses is a byproduct of which of the following?

In the measurement of a physical quantity $X = \frac{A^2 B}{C^{1/3} D^3}$,the percentage errors in the measurements of $A, B, C$,and $D$ are $2\%, 2\%, 4\%$,and $5\%$,respectively. The minimum percentage error in the measurement of $X$ is contributed by:

$A$ particle moves along the curve $y=x^2+2x$. The point on the curve such that the $x$ and $y$ coordinates of the particle change at the same rate is