Which of the following reagents would you use to separate $SO_4^{2-}$ ions from a solution containing a mixture of $SO_4^{2-}$ and $Cl^-$ ions?

The work function of a metallic surface is $5.01 \ eV$. Photo-electrons are emitted when light of wavelength $2000 \ \mathring{A}$ falls on it. The potential difference applied to stop the fastest photo-electrons is .............. $V$ $[h = 4.14 \times 10^{-15} \ eV \cdot s]$.

There is no $S-S$ bond in

The ensheathing of muscles is called:

Solid targets of different elements are bombarded by highly energetic electron beams. The frequency $(f)$ of the characteristic $X-$rays emitted from different targets varies with atomic number $(Z)$ as

In the adjoining circuit,the battery $E_1$ has an emf of $12 \, V$ and zero internal resistance,while the battery $E_2$ has an emf of $2 \, V$. If the galvanometer $G$ reads zero,then the value of the resistance $X$ (in $\Omega$) is