Understanding Electrostatic Induction

Riyaan is trying to understand what a capacitor is and how it functions in electronic devices. Can you help him?

• A capacitor is a type of resistor used to limit current flow.

• A capacitor is a device that converts electrical energy into mechanical energy.

• A capacitor is a battery that stores energy for long periods.

• A capacitor is a device that stores electrical energy in an electric field.

Answer explanation

A capacitor stores electrical energy in an electric field, allowing it to release energy when needed. This distinguishes it from resistors and batteries, which serve different functions in electronic devices.

Aarush is conducting an experiment in his physics class to understand the concept of capacitance. He learns that capacitance is a crucial property in electrical circuits. Can you define capacitance and its unit of measurement?

• Capacitance is measured in volts (V).

• Capacitance is defined as the ability to conduct electricity.

• Capacitance is measured in farads (F).

• Capacitance is measured in ohms (Ω).

Answer explanation

Capacitance is defined as the ability of a system to store electric charge, and it is measured in farads (F). This makes the correct choice clear, as volts (V) and ohms (Ω) are units for voltage and resistance, respectively.

Aarav is conducting an experiment with capacitors in his physics lab. What role do dielectrics play in capacitors?

• Dielectrics increase capacitance and energy storage in capacitors.

• Dielectrics have no effect on the performance of capacitors.

• Dielectrics decrease capacitance and energy storage in capacitors.

• Dielectrics are used to cool down capacitors during operation.

Answer explanation

Dielectrics are insulating materials placed between capacitor plates. They increase capacitance by allowing more charge to be stored for a given voltage, thus enhancing energy storage capabilities.

During a physics class, Alisha was curious about electric polarization in dielectrics. Can you explain this concept?

• Electric polarization in dielectrics is the alignment of dipoles within the material in response to an external electric field.

• Electric polarization is the movement of electrons to the surface of a conductor.

• Electric polarization occurs only in metals when heated.

• Electric polarization is the process of charging a dielectric by direct contact with a conductor.

Answer explanation

Electric polarization in dielectrics refers to the alignment of dipoles within the material when an external electric field is applied, making the correct choice the first one.

Naira is studying the structure and function of a parallel plate capacitor in her physics class.

• A parallel plate capacitor has two conductive plates separated by a dielectric, storing energy in an electric field when voltage is applied.

• A parallel plate capacitor uses a liquid medium to separate the plates and enhance conductivity.

• A parallel plate capacitor consists of a single conductive plate that generates a magnetic field.

• A parallel plate capacitor has three plates arranged in a triangular formation to store energy.

Answer explanation

A parallel plate capacitor consists of two conductive plates separated by a dielectric material. It stores energy in an electric field when a voltage is applied, making the first choice the correct description.

Saisha is conducting an experiment with a parallel plate capacitor. How does the presence of a dielectric affect the capacitance of her capacitor?

• The capacitance decreases.

• The capacitance becomes zero.

• The capacitance increases.

• The capacitance remains the same.

Answer explanation

The presence of a dielectric material between the plates of a capacitor increases its capacitance. This is because dielectrics reduce the electric field strength, allowing the capacitor to store more charge for the same voltage.

Divya is working on a project involving electronic circuits. She needs to list some common applications of capacitors in her design.

• Common applications of capacitors include filtering, coupling, decoupling, timing circuits, and energy storage.

• Power generation

• Signal amplification

• Data storage

Answer explanation

The correct choice lists common applications of capacitors, such as filtering, coupling, decoupling, timing circuits, and energy storage, which are essential in electronic circuit design.

Alisha is working on a physics project and needs to calculate the energy stored in a capacitor. What is the formula she should use?

• E = 1/2 * C * V^2

• E = C * V

• E = C * V^2 / 2

• E = 1/2 * C * I^2

Answer explanation

The correct formula for the energy stored in a capacitor is E = 1/2 * C * V^2, where E is energy, C is capacitance, and V is voltage. This formula accurately represents the relationship between these variables.

Naira is conducting an experiment with a capacitor. How does the energy stored in the capacitor change as she increases the voltage applied to it?

• The energy stored in a capacitor increases with the square of the voltage.

• The energy stored in a capacitor is directly proportional to the current flowing through it.

• The energy stored in a capacitor remains constant regardless of voltage changes.

• The energy stored in a capacitor decreases with the square of the voltage.

Answer explanation

The energy (E) stored in a capacitor is given by the formula E = 1/2 CV^2, where C is capacitance and V is voltage. As voltage increases, the energy stored increases with the square of the voltage, confirming the correct choice.

Arjun is working on a project that involves connecting capacitors in series. What happens to the total capacitance when capacitors are connected in series?

• The total capacitance remains the same.

• The total capacitance becomes zero.

• The total capacitance decreases.

• The total capacitance increases.

Answer explanation

When capacitors are connected in series, the total capacitance decreases. This is because the reciprocal of the total capacitance is the sum of the reciprocals of the individual capacitances, leading to a lower overall capacitance.