Capacitors and Inductors Quiz

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Questions and Answers

What is the effect of an inductor on direct current (DC)?

It acts like a short circuit. (correct)

It behaves like a resistor.

It acts as an open circuit.

It generates electricity.

Which property describes how the current through an inductor behaves?

It decreases over time.

It can change instantaneously.

It cannot change instantaneously. (correct)

It changes according to voltage fluctuations.

What happens to the energy stored in an ideal inductor?

It can only be used at the moment it is stored.

It becomes unavailable after the circuit is opened.

It is always dissipated as heat.

It can be retrieved at a later time. (correct)

How is the equivalent inductance of series-connected inductors calculated?

It is the sum of the individual inductances. Signup and view all the answers

What is the formula for calculating the equivalent inductance of parallel-connected inductors?

Reciprocal of the sum of the reciprocals of the individual inductances. Signup and view all the answers

Which factor does NOT affect the capacitance of a capacitor?

Material density of the plates Signup and view all the answers

What is the typical range of values for capacitors?

Picofarad (pF) to microfarad (µF) Signup and view all the answers

Which statement about nonlinear capacitors is true?

They can exhibit varying capacitance based on voltage. Signup and view all the answers

What relationship is illustrated in the equation $i = C \frac{dv}{dt}$?

The dependency of current on capacitance and rate of voltage change. Signup and view all the answers

What does equation $v = \frac{1}{C} \int i , dt + v(t_0)$ represent?

The voltage across a capacitor based on past current history. Signup and view all the answers

What is a characteristic of variable capacitors?

Their capacitance can be adjusted or varied. Signup and view all the answers

How is the capacitance of a capacitor affected by the spacing between its plates?

Decreased spacing leads to higher capacitance. Signup and view all the answers

What does the equation $w = \frac{1}{2} C v^2$ represent?

The energy stored in a capacitor Signup and view all the answers

Which type of capacitor is typically described by the dielectric material used?

Fixed capacitor Signup and view all the answers

Which statement about capacitors is incorrect?

Capacitors can dissipate energy. Signup and view all the answers

For two capacitors in series, the equivalent capacitance is calculated using which formula?

C_eq = \frac{C_1 C_2}{C_1 + C_2} Signup and view all the answers

If a capacitor with a capacitance of 10 μF is charged with a voltage of 12 V, what is the energy stored in the capacitor?

0.72 mJ Signup and view all the answers

What is the unit of inductance?

Henry Signup and view all the answers

What happens to a capacitor connected to a DC voltage source over time?

It reaches a fully charged state and stops current flow. Signup and view all the answers

Which factor does not directly increase the inductance of an inductor?

Increasing the length of the coil Signup and view all the answers

How does an ideal capacitor behave with respect to energy dissipation?

It stores energy and returns it without dissipation. Signup and view all the answers

What property does an inductor exhibit when current flowing through it changes?

Opposition to change in current Signup and view all the answers

Which equation can be used to calculate the energy stored in a capacitor in terms of charge?

$w = \frac{q^2}{2 C}$ Signup and view all the answers

What is the effect of adding more capacitance in parallel?

It allows higher energy storage capacity. Signup and view all the answers

What is the relationship called that describes the voltage across an inductor versus the current through it?

Voltage-current relationship Signup and view all the answers

In inductors, which of the following materials is commonly used as a core to enhance inductance?

Iron Signup and view all the answers

In a linear inductor, how is its inductance characterized?

Independent of current Signup and view all the answers

What range of inductance values do typical practical inductors have?

From a few microhenries to tens of henries Signup and view all the answers

Which of the following terms is NOT synonymous with an inductor?

Resistor Signup and view all the answers

What is the primary function of capacitors in electrical circuits?

To store energy in an electric field Signup and view all the answers

Which material configurations are typically found in the construction of capacitors?

Aluminium plates with air, paper, or mica dielectric Signup and view all the answers

How is capacitance defined mathematically?

$C = \frac{q}{v}$ Signup and view all the answers

What unit is used to measure capacitance?

Farad Signup and view all the answers

What factors influence the capacitance of a parallel-plate capacitor?

Plate surface area, distance between plates, and dielectric permittivity Signup and view all the answers

Which of the following statements about capacitors is true?

Capacitance is inversely proportional to the distance between the plates. Signup and view all the answers

What does the symbol '∈' represent in the capacitance formula for a capacitor?

Permittivity of the dielectric material Signup and view all the answers

In what applications are capacitors commonly utilized?

In tuning circuits of radio receivers and as dynamic memory elements in computer systems Signup and view all the answers

Study Notes

Capacitors

Capacitors store energy in an electric field.
Used in electronics, communications, computers, and power systems.
A capacitor consists of two conducting plates separated by an insulator (dielectric).
The amount of charge stored (q) is directly proportional to the applied voltage (v): q = Cv
Capacitance (C) is the constant of proportionality, measured in farads (F).
1 farad = 1 coulomb/volt
Capacitance depends on the physical dimensions of the capacitor, specifically:
- Surface area of the plates (larger area = greater capacitance)
- Distance between the plates (smaller distance = greater capacitance)
- Permittivity of the dielectric material (higher permittivity = greater capacitance)
Current-voltage relationship for a capacitor: i = C(dv/dt)
Energy stored in a capacitor: w = (1/2)Cv² or w = (1/2)(q²/C)

Inductors

Inductors store energy in a magnetic field.
Used in power supplies, transformers, radios, TVs, radars, and electric motors.
An inductor is a coil of conducting wire.
Current-voltage relationship for an inductor: v = L(di/dt)
Inductance (L) is a constant of proportionality, measured in Henrys (H).
1 henry = 1 volt-second/ampere
Inductance depends on physical dimensions:
- Number of turns (N)
- Length (l)
- Cross-sectional area (A)
- Permeability of the core material (µ)
Energy stored in an inductor: w = (1/2)Li²
Current through an inductor cannot change instantaneously.
An inductor acts like a short circuit to direct current(DC)

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Description

Test your knowledge on the principles of capacitors and inductors. This quiz covers key concepts including energy storage, capacitance, and the current-voltage relationships. Perfect for students studying electronics or electrical engineering.