The correct order of $S-S$ bond length in the following oxyanions is:
$(I)$ $S_2O_4^{2-}$ $(II)$ $S_2O_5^{2-}$ $(III)$ $S_2O_6^{2-}$

The input resistance of a common emitter transistor amplifier,if the output resistance is $500 \, k\Omega$,the current gain $\alpha = 0.98$ and power gain is $6.0625 \times 10^6$,is....$\Omega$

$A$ random variable $X$ takes the values $0, 1$ and $2$. If $P(X=1)=P(X=2)$ and $P(X=0)=0.4$,then the mean of the random variable $X$ is

The force required to move a body up a rough inclined plane is double the force required to prevent the body from sliding down the plane. The coefficient of friction,when the angle of inclination of the plane is $60^{\circ}$,is

The point $P$ is equidistant from $A(1, 3)$,$B(-3, 5)$,and $C(5, -1)$. Then $PA$ is equal to:

$A$ body of $5\, kg$ weight kept on a rough inclined plane of angle $30^\circ$ starts sliding with a constant velocity. Then the coefficient of friction is: