Two parallel plate capacitors identical in shape and size are filled with air and mica respectively. Which one has larger capacitance? Write proper relation in support of your answer.
Answers
Answer:
Two parallel plate capacitors identical in shape and size are filled with air and mica separately. ... So, the capacitance of a capacitor increases when a dielectric is inserted between them. The capacitor mica will have a larger capacity than the air capacitor because mica has a higher dielectric constant. 6.
The molecules in the insulating material between the plates of a capacitor are polarized by the charged plates. This produces a layer of opposite charge on the surface of the dielectric that attracts more charge onto the plate, increasing its capacitance.
Answer:
You perhaps know the equation, which shows that when a material with dielectric constant (or relative permitivity k) is placed to fill the space between the two plates, the capacitance gets multiplied by a factor of k compared to the capacitance you would get from the same two plates separated by empty space or vacuum.
Let me give a physical and qualitative explanation of why that happens.
Let’s start with a capacitor with vacuum between the two plates. You apply a voltage V between the plates. The capacitor’s plates will draw some momentary current and accumulate a charge on the plates (positive on one plate and negative on the other). This will also create an electric field E between the plates such that V = E . d where d is the distance between the plates. E is proportional to the charge Q on each plate. As E is also proportional to V, so Q is also proportional to V. The ratio between Q and V is called capacitance C.
C = Q/V