The value of $\sqrt{12\sqrt{5} + 2\sqrt{55}}$ is

Which of the following metallic hydroxides does not dissolve in a sodium hydroxide solution?

When radiation of wavelength $\lambda$ is incident on a metallic surface,the stopping potential is $4.8 \ V$. If the surface is illuminated with radiation of double the wavelength,then the stopping potential becomes $1.6 \ V$. The threshold wavelength for the surface is:

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

$X=x$	$P(X=x)$
$0$	$0.4$
$1$	$0.3$
$2$	$0.1$
$3$	$0.1$
$4$	$0.1$

The variance of $X$ is:

$A$ polaroid is placed at $45^{\circ}$ to an incoming light of intensity $I_0$. Now,the intensity of light passing through the polaroid after polarization would be:

Larger number of oxidation states are exhibited by the actinoids than those by the lanthanoids,the main reason being