The principle of controlled chain reaction is used in

In a series $LCR$ circuit,$R=300 \Omega, L=0.9 \text{ H}, C=2.0 \mu\text{F}$ and $\omega=1000 \text{ rad/s}$,then the impedance of the circuit is: (in $\Omega$)

$A$ transistor is used as a common emitter amplifier with a load resistance of $2 \ k\Omega$. The input resistance is $150 \ \Omega$. Base current is changed by $20 \ \mu A$,which results in a change in collector current by $1.5 \ mA$. The voltage gain of the amplifier is

The transformed equation of $3x^2 + 3y^2 + 2xy = 2$,when the coordinate axes are rotated through an angle of $45^{\circ}$,is

The following compounds have been arranged in order of their increasing thermal stabilities. Identify the correct order :
$K_2CO_3(I), MgCO_3(II), CaCO_3(III), BeCO_3(IV)$

The hydride ion $H^{-}$ is a stronger base than the hydroxide ion $OH^{-}$. If sodium hydride $(NaH)$ is dissolved in water,which of the following reactions will occur?