Find the oxidation state of sodium in $Na_{2}O_{2}$.

The probability distribution of a random variable $X$ is given below:

$X = x$	$0$	$1$	$2$	$3$
$P(X = x)$	$\frac{1}{10}$	$\frac{2}{10}$	$\frac{3}{10}$	$\frac{4}{10}$

Then the variance of $X$ is

The use of anti-histamine,adrenaline,and steroids quickly reduces the symptoms of:

Which of the following is a bactericidal antibiotic?

The energy-releasing metabolic process in which substrate is oxidized without an external electron acceptor is called:

In an $AC$ generator,a coil with $N$ turns,all of the same area $A$ and total resistance $R$,rotates with frequency $\omega$ in a magnetic field $B$. The maximum value of $emf$ generated in the coil is