If the slope of one of the pair of lines represented by $2x^2 + 3xy + Ky^2 = 0$ is $2$,then the angle between the pair of lines is

The work of $146 \, kJ$ is performed in order to compress one kilo mole of a gas adiabatically,and in this process,the temperature of the gas increases by $7 \, ^oC$. The gas is $(R = 8.3 \, J \, mol^{-1} \, K^{-1})$.

The $\pi$-acid ligand which uses its $d$-orbital during synergic bonding in its complex compound is

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

If $\overrightarrow{a}=-\hat{i}+\hat{j}+2 \hat{k}$,$\overrightarrow{b}=2 \hat{i}-\hat{j}-\hat{k}$ and $\overrightarrow{c}=-2 \hat{i}+\hat{j}+3 \hat{k}$,then the angle between $2 \overrightarrow{a}-\overrightarrow{c}$ and $\overrightarrow{a}+\overrightarrow{b}$ is

If the best and the worst paper never appear together,then in how many ways can six examination papers be arranged?