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ratio of capacitance of capacitor is given by charge\potential
capacitor is a device to store charge .it is based on the concept that when the potential of the capacitor is decreased it can gain some more charge so Q = CV where V is potential and Q is the charge stored then C is the capacitance. capacitance is the ability of the capacitor to store charge. expression for capacitance is C=ɛA/d where ɛis permittivity and A is area of capacitor plates ,d is plate separation.
The capacitor will hold the charge, until it leaks off due to resistances in the dielectric or external.
Capacitance is quite literally the capacity to hold charge at a given potential difference.
capacitance, in electricity, capability of a body, system, circuit, or device for storing electric charge. Capacitance is expressed as the ratio of stored charge in coulombs to the impressed potential difference in volts. The resulting unit of capacitance is the farad [for Michael Faraday]. In an electric circuit the device designed to store charge is called a capacitor. An ideal capacitor, i.e., one having no resistance or inductance, may be spoken of as a capacitance. When an alternating current flows through a capacitor, the capacitor produces a reactance that resists the current (see impedance). While every element of a circuit has some capacitance, it is a goal of good design to reduce such unwanted or stray capacitance to a minimum.
(a) Charge Will increase (b) Potential difference will stay the same (c) Capacitance will increase (d) Stored energy will decrease
capacitance is inversely proportional to the separation between the platesproof :-electric field is ;- k/E0where k- surface charge density of the plateand potential difference is given by kl/E0and, capacitance by C=Q/Vso, capacitance is inversely proportional to separation between the plates
Theæ definition of farad is as follows; SI unit of capacitance, formally defined to be the capacitance of a capacitor between the plates of whichæthere appears a potential difference of one volt when it is charged by a quantity of electricity equal to one coulomb.
we use charge stored in the capacitor as our variable (remember it one of the three variable). so the potential difference across the capacitor is --charge stored in the capacitor at that instance/capacitance of the capacitor. potential difference across resistor is --resistance* differential of charge with respect to time. potential difference across inductor is -- inductance*double difference of charge with respect to the time. If there is no voltage source attached with the network then sum of the total potential difference is equal to zero hence your solution.........L*d^2(q)/dt^2 + R*d(q)/dt + q/c =0
The rating or 'size' of a capacitor, called its "capacitance", is related the amount of charge the capacitor can store, to the amount of energy it holds when it stores some charge, and to the opposition of the capacitor to the apparent flow of alternating current through it. If a capacitor has a capacitance of 1 farad, then -- One coulomb of charge stripped off of one plate and added to the other plate produces 1 volt of potential difference between the plates. -- The energy stored in the capacitor is 1/2 the square of the voltage across it. -- Its impedance is (0.159 divided by the frequency) ohms. The farad is an enormous capacitance. A typical capacitor used in a 'lumped' circuit ... the kind of construction where you would buy a capacitor and solder it in ... has a capacitance in the range of maybe 10 picofarads (trillionths of a farad) to maybe 100 microfarads (millionths of a farad).
The units of capacitance are called farads. A one farad capacitor is a capacitor with 1 volt potential difference with 1 coulomb of charge on the capacitor, C = Q/V or Q=CV So the charge held on your capacitor is Q = CV = 9Volts * 0.40*10-6Farads=3.6*10-6 Coulombs
capacitance