Which of the following alkali metals reacts directly with nitrogen to form a nitride?

Which of the following has the lowest thermal stability?

The same current is flowing in two alternating circuits. The first circuit contains only an inductor and the second contains only a capacitor. If the frequency of the $e.m.f.$ of the $ac$ source is increased,what will be the effect on the value of the current in these circuits?

$A$ magnetic needle is kept in a non-uniform magnetic field. It experiences

If $z_1, z_2$ are two complex numbers satisfying $\left|\frac{z_1-3 z_2}{3-z_1 \bar{z}_2}\right|=1$ and $\left|z_1\right| \neq 3$,then $\left|z_2\right|$ is equal to

The largest group of insecticides produced by plants is .......