Mention any two factors on which the capacitance of a parallel plate capacitor depends.
Answer
594.3k+ views
Hint: Capacitor is a device used to store charges in an electric circuit. Capacitor has two plates separated by a distance having equal and opposite charges. Derive the expression for capacitance of a parallel plate capacitor using the equation for potential difference and electric field between two plates. Then, using this obtained expression, find the factors on which it’s capacitance is dependent.
Complete answer:
Electric field between the plates of parallel plate capacitors given by,
$E= \dfrac {\sigma}{K{\epsilon}_{0}}$ ...(1)
Potential difference between two plates is given by,
$V=Ed$
Substituting equation. (1) in above equation we get,
$V= \dfrac {\sigma d}{K{\epsilon}_{0}}$ ...(2)
But, $\sigma = \dfrac {Q}{A} $
Substituting this value in the equation. (2) we get,
$V= \dfrac {({Q}/{A})d}{K {\epsilon}_{0}}$
$\therefore V= \dfrac {Qd}{K {\epsilon}_{0}A}$ ...(3)
Now, capacitance of a capacitor is given by,
$C= \dfrac {Q}{V}$ ...(4)
Substituting equation. (4) in equation. (3) we get,
$C= \dfrac {Q} {\dfrac {Qd}{K {\epsilon}_{0}A}}$
$\therefore C= \dfrac {K {\epsilon}_{0}A}{d}$
This is the expression for capacitance of a parallel plate capacitor.
From the above equation, it can be understood that the capacitance depends on the dielectric constant of the medium between the plates, area of each plate and distance between the plates.
Hence, capacitance of a parallel plate capacitor depends on the dielectric constant of the medium between the plates, area of each plate and distance between the plates.
Note:
Amount of charge a capacitor can store depends on two factors. First is the voltage and second is the physical characteristics of the capacitors. When a dielectric medium is placed between the two parallel plates of the capacitor, it’s capacity of storing the energy increases. It’s energy increases by a factor K which is called a dielectric constant. If you want to increase the capacitance of parallel plate capacitors then increase the area, decrease the separation between two plates and use a dielectric medium.
Complete answer:
Electric field between the plates of parallel plate capacitors given by,
$E= \dfrac {\sigma}{K{\epsilon}_{0}}$ ...(1)
Potential difference between two plates is given by,
$V=Ed$
Substituting equation. (1) in above equation we get,
$V= \dfrac {\sigma d}{K{\epsilon}_{0}}$ ...(2)
But, $\sigma = \dfrac {Q}{A} $
Substituting this value in the equation. (2) we get,
$V= \dfrac {({Q}/{A})d}{K {\epsilon}_{0}}$
$\therefore V= \dfrac {Qd}{K {\epsilon}_{0}A}$ ...(3)
Now, capacitance of a capacitor is given by,
$C= \dfrac {Q}{V}$ ...(4)
Substituting equation. (4) in equation. (3) we get,
$C= \dfrac {Q} {\dfrac {Qd}{K {\epsilon}_{0}A}}$
$\therefore C= \dfrac {K {\epsilon}_{0}A}{d}$
This is the expression for capacitance of a parallel plate capacitor.
From the above equation, it can be understood that the capacitance depends on the dielectric constant of the medium between the plates, area of each plate and distance between the plates.
Hence, capacitance of a parallel plate capacitor depends on the dielectric constant of the medium between the plates, area of each plate and distance between the plates.
Note:
Amount of charge a capacitor can store depends on two factors. First is the voltage and second is the physical characteristics of the capacitors. When a dielectric medium is placed between the two parallel plates of the capacitor, it’s capacity of storing the energy increases. It’s energy increases by a factor K which is called a dielectric constant. If you want to increase the capacitance of parallel plate capacitors then increase the area, decrease the separation between two plates and use a dielectric medium.
Recently Updated Pages
Which of the following graphs shows the variation of class 12 physics CBSE

Draw a labelled diagram of the human male reproductive class 12 biology CBSE

Describe the experiment to compare the emf of two cells class 12 physics CBSE

What is standard hydrogen electrode

What is conventional current and electric current class 12 physics CBSE

2Bromopentane is treated with an alcoholic KOH solution class 12 chemistry CBSE

Trending doubts
Draw a labelled sketch of the human eye class 12 physics CBSE

Which are the Top 10 Largest Countries of the World?

A member of Simon commission later became Prime Minister class 12 social science CBSE

Draw ray diagrams each showing i myopic eye and ii class 12 physics CBSE

Give one example of a reptile that is viviparous class 12 biology CBSE

Which is the correct genotypic ratio of mendel dihybrid class 12 biology CBSE

