Impedance and Phase Factor in AC Circuits

What is the value of inductance $\mathrm{L}$ for which the current is maximum in a series LCR circuit with $\mathrm{C}=10 \mathrm{\mu F}$ and $\mathrm{\omega }=1000 {\mathrm{s}}^{-1}$?

The peak voltage in a $220 \mathrm{V}$,$50 \mathrm{Hz} \mathrm{AC}$source is:

If coil is open, then $\mathrm{L}$ and $\mathrm{R}$ becomes 

In an LCR-series ac circuit, the voltage across each of the component $\mathrm{L}, \mathrm{C} \mathrm{and} \mathrm{R}$ is $50 \mathrm{V}$. The voltage across the LC-combination will be-

The phase difference between the AC circuit and emf is $\raisebox{1ex}{$\mathrm{\pi }$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$, which of the following cannot be the constituent of the circuit?

Cotyledons are also called-