Which of the following substances releases nitrogen gas upon thermal decomposition?

Energy is being emitted from the surface of a black body at $127^{\circ}C$ temperature at the rate of $1.0 \times 10^6 \ J/\text{s} \cdot \text{m}^2$. The temperature of the black body at which the rate of energy emission is $16.0 \times 10^6 \ J/\text{s} \cdot \text{m}^2$ will be ......... $^{\circ}C$.

In chromite ore,the oxidation number of iron and chromium are respectively

$A$ steel meter scale is to be ruled so that millimeter intervals are accurate within about $5 \times 10^{-5} \ mm$ at a certain temperature. The maximum temperature variation allowable during the ruling is .......... $^oC$ (Coefficient of linear expansion of steel $\alpha = 10 \times 10^{-6} \ K^{-1}$)

If the extremities of a diagonal of a square are $(1, -2, 3)$ and $(2, -3, 5)$,then the length of its side is

Seven white balls and three black balls are randomly arranged in a row. The probability that no two black balls are placed adjacently is