An example of a double salt is

Match the following:

$1$. Burning candle	$i$. Line spectrum
$2$. Sodium vapour	$ii$. Continuous spectrum
$3$. Bunsen flame	$iii$. Band spectrum
$4$. Dark lines in solar spectrum	$iv$. Absorption spectrum

If $f(x) = \sqrt{\frac{x - \sin x}{x + \cos^2 x}}$,then $\lim_{x \to \infty} f(x)$ is

The major product of the following reaction is:

In carbon monoxide $(CO)$,how are the carbon and oxygen atoms bonded?

$A$ transverse wave propagating on a stretched string of linear density $3 \times 10^{-4} ~kg ~m^{-1}$ is represented by the equation $y=0.2 \sin (1.5 x+60 t)$,where $x$ is in metres and $t$ is in seconds. The tension in the string (in newton) is