In acidic medium, only iodide ions (I\(^-\)) can be oxidized by oxygen to form iodine (\( \text{I}_2 \)). The reaction is as follows: \[ 4 \text{I}^- + 4 \text{H}^+ + \text{O}_2 \rightarrow 2 \text{I}_2 (s) + 2 \text{H}_2\text{O} (l). \] Chloride (Cl\(^-\)) and bromide (Br\(^-\)) ions are not oxidized by oxygen in acidic medium because their reduction potentials are not favorable for such oxidation under standard conditions.
Calculate the potential for half-cell containing 0.01 M K\(_2\)Cr\(_2\)O\(_7\)(aq), 0.01 M Cr\(^{3+}\)(aq), and 1.0 x 10\(^{-4}\) M H\(^+\)(aq).

In the given figure, the blocks $A$, $B$ and $C$ weigh $4\,\text{kg}$, $6\,\text{kg}$ and $8\,\text{kg}$ respectively. The coefficient of sliding friction between any two surfaces is $0.5$. The force $\vec{F}$ required to slide the block $C$ with constant speed is ___ N.
(Given: $g = 10\,\text{m s}^{-2}$) 
Two circular discs of radius \(10\) cm each are joined at their centres by a rod, as shown in the figure. The length of the rod is \(30\) cm and its mass is \(600\) g. The mass of each disc is also \(600\) g. If the applied torque between the two discs is \(43\times10^{-7}\) dyne·cm, then the angular acceleration of the system about the given axis \(AB\) is ________ rad s\(^{-2}\).
