Test: Electricity - SSC CGL MCQ

The intrinsic property of protons and electrons in relation to electric charge is their type. Protons carry a positive charge and electrons carry a negative charge. This fundamental property of particles forms the basis of understanding electrical interactions in various phenomena.

Like charge bodies are described to repel each other, while unlike charge bodies attract each other according to the text. This principle underpins the behavior of charged objects and is essential in understanding the dynamics of electrical interactions.

According to Coulomb's Law, the electrostatic force of interaction between two stationary point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. This means that the force between two charges increases as the product of their charges increases and decreases as the square of the distance between them increases.

The electric field intensity (E) at any point is defined as the electrostatic force (F) acting per unit positive test charge at that point. This means it represents the force experienced by a unit positive test charge at that specific location in the electric field generated by other charges. It is a measure of the strength of the electric field at that point.

An electric field line represents the direction of the electric field vector at a specific point in space. The concept of electric field lines helps to visualize the direction and intensity of the electric field. These lines indicate the path a positive test charge would follow if placed in the electric field at that point. Remember, the relative closeness of the lines signifies the strength of the electric field—closer lines indicate a stronger field, while more spaced-out lines represent a weaker field.

The key disparity between conductors and insulators lies in their electron mobility. Conductors, such as metals, possess a large number of free electrons, enabling them to conduct electricity effectively. In contrast, insulators like wood and rubber lack free electrons within their structure, impeding the flow of electricity. This distinction in electron availability determines the contrasting electrical conductive properties of conductors and insulators.

The relationship between resistivity and temperature for metals is such that the resistivity of metals increases with an increase in temperature. This is due to the positive temperature coefficient of resistance that metals exhibit. As temperature rises, the atoms in the metal vibrate more vigorously, impeding the flow of electrons and thus increasing resistance. This phenomenon is crucial to consider in various applications involving metal conductors.

Alloys like nichrome and constantan exhibit a resistivity that is higher than that of metals but lower than that of semiconductors. This unique property makes these alloys valuable in applications where a specific level of resistance is required. Nichrome, for example, is often used in heating elements due to its high resistivity and ability to withstand high temperatures, making it a crucial component in various electrical devices.

Ohm's law states that the potential difference (V) across a conductor is directly proportional to the electric current (I) flowing through it, with the constant of proportionality being the resistance (R) of the conductor. This fundamental law in electrical circuits forms the basis for understanding how voltage, current, and resistance are interrelated in a circuit.

Kirchhoff's current law, also known as Kirchhoff's first law, demonstrates the principle of conservation of charge in an electrical circuit. It states that the algebraic sum of currents entering a junction in a circuit is equal to the sum of currents leaving the junction, representing the law of conservation of charge, which is a fundamental concept in electrical engineering.

When an electric current is passed through an acidic or basic solution, causing the solution to decompose into positive and negative ions, this phenomenon is known as electrolysis. In electrolysis, the positive ions gather at the negative electrode (cathode) while the negative ions accumulate at the positive electrode (anode). This process is essential in various applications, including electroplating where a base metal is coated with a layer of a more expensive metal.

The unit of electric energy equivalent to 3.6 × 10⁶ joules is 1 kilowatt-hour (kWh). This unit is commonly used to measure energy consumption in households and is often referred to as '1 unit' of electricity. Understanding this unit is crucial for assessing and managing electricity usage effectively.

The friction between two suitable materials can generate static electricity. This process involves the transfer of charges between the materials, leading to one object gaining a positive charge and the other acquiring a negative charge. Understanding this phenomenon is crucial in various practical applications involving electricity.

The electric field intensity is inversely proportional to the square of the distance from a point charge. As you move farther away from a point charge, the electric field intensity decreases as the square of the distance increases. This relationship highlights how the strength of the electric field weakens as you move further away from the charge source.

A capacitor serves the crucial role of storing and releasing electric charge in an electrical circuit. It can accumulate a significant amount of charge without altering its physical dimensions. When connected in a circuit, capacitors store energy in the form of an electric field between their plates. This stored energy can be discharged back into the circuit when required, making capacitors essential components in various electronic devices and systems.