Name the chronic respiratory disorder caused mainly by cigarette smoking.

Which of the following alkali metal ions has the lowest ionic mobility in an aqueous solution?

One turn of insulated wire in the form of a planar square frame with side $l = 0.2\,m$ and resistance $R = 1\,\Omega$ is placed in a uniform magnetic field perpendicular to the plane of the frame. The current passing through the turn when the magnetic field starts to decrease at a constant rate of $0.1\,T/s$ is......$mA$.

In which of the following compounds does the transition metal have a zero oxidation state?

If $\alpha, \beta, \gamma$ are the roots of the equation $x^3 + 4x + 1 = 0$,then $(\alpha + \beta)^{-1} + (\beta + \gamma)^{-1} + (\gamma + \alpha)^{-1} = $

The velocities of three particles of masses $20 \ g$,$30 \ g$ and $50 \ g$ are $10 \hat{i}$,$10 \hat{j}$ and $10 \hat{k}$,respectively. The velocity of the centre of mass of the three particles is