Advertisements
Advertisements
प्रश्न
A parallel-plate capacitor has plate area 25⋅0 cm2 and a separation of 2⋅00 mm between the plates. The capacitor is connected to a battery of 12⋅0 V. (a) Find the charge on the capacitor. (b) The plate separation is decreased to 1⋅00 mm. Find the extra charge given by the battery to the positive plate.
Advertisements
उत्तर
Given :
Area of the plate , `A = 25 "cm"^2 = 25 xx 10^-4 "m"^2`
Separation between the plates, `d = 2 "mm" = 2 xx 10^-3 "m"`
Potential difference between the plates, V = 12 V
The capacitance of the given capacitor is given by
`C = (∈_0A)/d`
= `((8.85 xx 10^-12) xx (25 xx 10^-4))/((2 xx 10^-3))`
= `11.06 xx 10^-12 "F"`
(a) Charge on the capacitor is given by
Q = CV
= `11.06 xx 10^-12 xx 12`
= `1.33 xx 10^-10 "C"`
(b) When the separation between the plates is decreased to 1 mm , the capacitance `C^'` can be calculated as :
`C^' = (∈_0A)/d`
= `((8.85 xx 10^-12) xx (25 xx 10^-4))/(1 xx 10^-3)`
= `22.12 xx 10^-12 "F"`
Charge on the capacitor is given by
`Q^' = C^'V`
= `22.12 xx 10^-12 xx 12`
= `2.65 xx 10^-10 "C"`
Extra Charge
= `(2.65 xx 10^-10 - 1.32 xx 10^-10) C`
= `1.33 xx 10^-10 "C"`
APPEARS IN
संबंधित प्रश्न
A bulb is connected in series with a variable capacitor and an AC source as shown. What happens to the brightness of the bulb when the key is plugged in and capacitance of the capacitor is gradually reduced?
Define capacitor reactance. Write its S.I units.
A capacitor of capacitance ‘C’ is being charged by connecting it across a dc source along with an ammeter. Will the ammeter show a momentary deflection during the process of charging? If so, how would you explain this momentary deflection and the resulting continuity of current in the circuit? Write the expression for the current inside the capacitor.
A cylindrical capacitor is constructed using two coaxial cylinders of the same length 10 cm and of radii 2 mm and 4 mm. (a) Calculate the capacitance. (b) Another capacitor of the same length is constructed with cylinders of radii 4 mm and 8 mm. Calculate the capacitance.
Each capacitor shown in figure has a capacitance of 5⋅0 µF. The emf of the battery is 50 V. How much charge will flow through AB if the switch S is closed?
The separation between the plates of a parallel-plate capacitor is 0⋅500 cm and its plate area is 100 cm2. A 0⋅400 cm thick metal plate is inserted into the gap with its faces parallel to the plates. Show that the capacitance of the assembly is independent of the position of the metal plate within the gap and find its value.
A sphercial capacitor is made of two conducting spherical shells of radii a and b. The space between the shells is filled with a dielectric of dielectric constant K up to a radius c as shown in figure . Calculate the capacitance.
Obtain an expression for equivalent capacitance when three capacitors C1, C2 and C3 are connected in series.
Define ‘capacitance’. Give its unit.
For the given capacitor configuration
- Find the charges on each capacitor
- potential difference across them
- energy stored in each capacitor.
Dielectric constant for a metal is ______.
The capacitance of a parallel plate capacitor is 60 µF. If the distance between the plates is tripled and area doubled then new capacitance will be ______.
A leaky parallel plate capacitor is filled completely with a material having dielectric constant K = 5 and electric conductivity σ = 7.4 × 10-12 Ω-1 m-1. If the charge on the plate at the instant t = 0 is q = 8.85 µC, then the leakage current at the instant t = 12 s is ______ × 10-1 µA.
Current versus time and voltage versus time graphs of a circuit element are shown in figure.
 |
 |
The type of the circuit element is ______.
Calculate equivalent capacitance of the circuit shown in the Figure given below:
What is the SI unit of capacitance?
Which statement lists the factors on which capacitance depends?
In a series combination, which statement describes the potential difference across each capacitor?
In a series combination, which capacitor gets a larger potential difference?
