If the angles of a triangle are in the ratio $1: 1: 4$,then the ratio of the perimeter of the triangle to its largest side is

$A$ wire has a resistance of $12 \, \Omega$. It is bent in the form of an equilateral triangle. The effective resistance between any two corners of the triangle is:

Conifers differ from grasses in the

$A$ vibrating string of certain length $l$ under a tension $T$ resonates with a mode corresponding to the first overtone (third harmonic) of an air column of length $75\, cm$ inside a tube closed at one end. The string also generates $4\, beats$ per second when excited along with a tuning fork of frequency $n$. Now when the tension of the string is slightly increased,the number of beats reduces to $2\, per second$. Assuming the velocity of sound in air to be $340\, m/s$,the frequency $n$ of the tuning fork in $Hz$ is

Helium mixed with oxygen is used in the treatment of

$Fe_2Cr_2O_4 + Na_2CO_3 + O_2$ $\xrightarrow{\text{Fusion}} [X]$ $\xrightarrow[H_2O]{H^+} [Y]$ $\xrightarrow{H_2O_2/H^+} [Z]$
Which of the following statements is true for the compounds $[X], [Y]$ and $[Z]$?