Which of the following compounds is formed in the borax bead test?

$A$ network of four capacitors with capacitances $C_1 = C$,$C_2 = 2C$,$C_3 = 3C$,and $C_4 = 4C$ is connected to a battery of voltage $V$ as shown in the figure. The ratio of the charges on $C_2$ and $C_4$ is

$A$ $TV$ transmitter has a range of $50 \ km$. The height of the $TV$ transmitter is . . . . . . (Radius of the earth,$R_e = 6.4 \times 10^6 \ m$). (in $m$)

Which of the following alkaline earth metals shows anomalous behavior and has an electronegativity similar to that of aluminum?

The coil in a moving coil galvanometer experiences a torque proportional to the current passing through it. If a steady current $i$ is passed through it,the steady deflection of the coil is found to be $90^o$. Now,the steady current is switched off and a charge $q$ is suddenly passed through the coil. If the coil has $N$ turns of area $A$ and its moment of inertia is $I$ about the axis of rotation,then the maximum angle through which it deflects upon passing charge $q$ is:

Farmers in a particular region were concerned that premature yellowing of leaves of a pulse crop might cause a decrease in the yield. Which treatment could be most beneficial to obtain maximum seed yield?