Which of the following statements is not true?

$A$ mass $M$,attached to a horizontal spring,executes $S.H.M.$ with amplitude $A_1$. When the mass $M$ passes through its mean position,a smaller mass $m$ is placed over it and both of them move together with amplitude $A_2$. The ratio of $\left( \frac{A_1}{A_2} \right)$ is

Ammonia with excess of $Cl_2$ forms:

$6.023 \times 10^{22}$ molecules are present in $10 \text{ g}$ of a substance '$X$'. The molarity of a solution containing $5 \text{ g}$ of substance '$X$' in $2 \text{ L}$ solution is ........... $\times 10^{-3} \text{ M}$.

If a line in space makes angles $\alpha, \beta,$ and $\gamma$ with the coordinate axes, then the value of $\cos 2\alpha + \cos 2\beta + \cos 2\gamma + \sin^2 \alpha + \sin^2 \beta + \sin^2 \gamma$ is equal to:

$A$ black body radiates energy at the rate of $E \text{ W/m}^2$ at a high temperature $T \text{ K}$. When the temperature is reduced to $\left(\frac{T}{2}\right) \text{ K}$,the radiant energy is