| List- I (Layer of atmosphere) | List- II (Approximate height over earth's surface) | ||
| A. | F1-Layer | I. | 10 km |
| B. | D-Layer | II. | 170-190 km |
| C. | Troposphere | III. | 100 km |
| D. | E-layer | IV. | 65-75 km |
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: $g = 10\,\text{m s}^{-2}$) 
The equivalent resistance between the points \(A\) and \(B\) in the given circuit is \[ \frac{x}{5}\,\Omega. \] Find the value of \(x\). 
Method used for separation of mixture of products (B and C) obtained in the following reaction is: 