$A$ spherical portion has been removed from a solid sphere having a charge distributed uniformly in its volume as shown in the figure. The electric field inside the emptied space is

In the figure shown, if the internal resistance of the battery is $1\, \Omega$, the reading of the ammeter will be ............... $A$.

$Ge$ and $Si$ diodes conduct at $0.3 \ V$ and $0.7 \ V$ respectively. In the following figure,if the $Ge$ and $Si$ diode connections are reversed,the value of $V_0$ changes by .....$V$.

The number of possible enantiomeric pairs that can be produced during mono-chlorination of $2$-methylbutane is

The current through an ideal $PN$-junction diode shown in the following circuit diagram will be ..... $mA$.

Consider an ionic solid $M X$ with $NaCl$ structure. Construct a new structure $( Z )$ whose unit cell is constructed from the unit cell of $M X$ following the sequential instructions given below. Neglect the charge balance.

$(i)$ Remove all the anions ( $X$ ) except the central one

$(ii)$ Replace all the face centered cations $(M)$ by anions $(X)$

$(iii)$ Remove all the corner cations $(M)$

$(iv)$ Replace the central anion ( $X$ ) with cation $(M)$

The value of $\left(\frac{\text { number of anions }}{\text { number of cations }}\right)$ in $Z$ is. . . . .