derive an expression for the energy stored in a capacitor. show that w...
Energy Stored in a Capacitor
When a capacitor is charged, energy is stored in the electric field between its plates. The amount of energy stored in a capacitor can be expressed as:
E = 1/2 CV^2
Where E is the energy stored in joules, C is the capacitance in farads, and V is the voltage across the capacitor in volts.
Loss of Energy When Two Conductors Share Charges
When two conductors share charges by being brought into electric contact, there is a loss of energy due to several factors.
Resistance of the Conductors
When two conductors are brought into contact, there is a finite resistance between them. This resistance causes a voltage drop, which results in a loss of energy. The amount of energy lost due to resistance can be calculated using Ohm's law:
E = I^2Rt
Where E is the energy lost in joules, I is the current flowing through the resistance in amperes, R is the resistance in ohms, and t is the time in seconds.
Heat Generation
When current flows through a resistance, heat is generated due to the Joule heating effect. This heat represents a loss of energy from the system. The amount of heat generated is proportional to the square of the current flowing through the resistance and the resistance itself.
Electromagnetic Radiation
When charges are moved or accelerated, electromagnetic radiation is emitted. This radiation represents a loss of energy from the system. The amount of radiation emitted is proportional to the acceleration of the charges and the square of the frequency of the radiation.
Conclusion
In summary, whenever two conductors share charges by being brought into electric contact, there is a loss of energy due to the resistance of the conductors, heat generation, and electromagnetic radiation. To minimize these losses, it is important to use low-resistance conductors and minimize the amount of time the conductors are in contact.