Explain the principle, construction and working of a cyclotron with the help of a labelled diagram. State its two limitations.

A wire with an area of cross section $10 {\mathrm{mm}}^2$ has resistance $5\Omega$,when a potential difference across its ends is $25 \mathrm{V}$.calculate the drift velocity of the electron. Given the number density of electrons is $5\times {10}^{20} \mathrm{electron}/{\mathrm{m}}^3$.

Given three resistors of resistances $1 \Omega , 2\Omega and 3\Omega$. How will you combine them to get an equivalent resistance of $\frac{11}{5}\Omega$..