Acetaldehyde cannot give:

Soil erosion can be prevented by

$A$ wire suspended vertically from one of its ends is stretched by attaching a weight of $200 \ N$ to the lower end. The weight stretches the wire by $1 \ mm$. The elastic energy stored in the wire is ......... $J$.

Which one of the following elements reduces $NaOH$ to $Na$?

If $\vec{a}, \vec{b}, \vec{c}$ are mutually perpendicular vectors having magnitudes $1, 2, 3$ respectively,then $[\vec{a}+\vec{b}+\vec{c} \quad \vec{b}-\vec{a} \quad \vec{c}]=$

In the photoelectric effect,if the work functions of $Li$,$Na$,and $Rb$ are $2.41 \ eV$,$2.30 \ eV$,and $2.09 \ eV$ respectively,what could be the approximate work function of $K$ in $eV$?