What property of objects is best measured by their capacitance?
the ability to conduct electric current
the ability to distort an external electrostatic field
the ability to store charge
The correct answer and explanation is:
The correct answer is: the ability to store charge.
Explanation:
Capacitance is a fundamental property of objects, particularly electrical conductors, that describes their ability to store electric charge when subjected to a voltage. It is defined as the ratio of the electric charge ((Q)) stored on the object to the potential difference ((V)) across it:
[
C = \frac{Q}{V}
]
Where (C) is the capacitance, measured in farads (F). A higher capacitance means the object can store more charge for a given voltage.
Capacitance is most commonly associated with capacitors, which are devices designed specifically to store charge in electrical circuits. A capacitor typically consists of two conductive plates separated by an insulating material (called a dielectric). When a voltage is applied across the plates, opposite charges accumulate on each plate, creating an electric field in the dielectric. This stored charge can later be released to perform work in the circuit.
The property of storing charge has several practical applications:
- Energy Storage: Capacitors temporarily store energy in the form of an electric field, which is useful in applications like power supply stabilization and energy smoothing.
- Signal Filtering: Capacitors can block direct current (DC) while allowing alternating current (AC) to pass, making them essential in filters and tuning circuits.
- Timing Circuits: Capacitors work with resistors to set time constants in circuits, which are used in oscillators, clocks, and delay circuits.
Capacitance depends on the geometry of the object and the properties of the materials involved. For example, larger surface areas, smaller distances between plates, and dielectrics with higher permittivity increase capacitance.
Thus, capacitance fundamentally measures an object’s ability to store charge and plays a crucial role in both theoretical and practical aspects of electronics and electromagnetism.