The energy and capacity of a charged parallel plate capacitor are $U$ and $C$ respectively. Now a dielectric slab of $\in _r = 6$ is inserted in it then energy and capacity becomes  (Assume charge on plates remains constant)

Putting a dielectric substance between two plates of condenser, capacity, potential and potential energy respectively

What are called polar molecules and non-polar molecules ? Both are Give examples. 

If a dielectric substance is introduced between the plates of a charged air-gap capacitor. The energy of the capacitor will

A parallel plate condenser is connected with the terminals of a battery. The distance between the plates is $6\,mm$. If a glass plate (dielectric constant $K = 9$) of $4.5\,mm$ is introduced between them, then the capacity will become.......$times$

A capacitor of capacitance $15 \,nF$ having dielectric slab of $\varepsilon_{r}=2.5$ dielectric strength $30 \,MV / m$ and potential difference $=30\; volt$ then the area of plate is ....... $ \times 10^{-4}\; m ^{2}$