Static and Current Electricity Quiz for Grade 9

Sodium oxide is a chemical compound formed by the combination of sodium (Na) and oxygen (O). Each sodium atom has a valence of +1, while oxygen has a valence of -2. To balance the charges, two sodium atoms are required for every one oxygen atom, resulting in the formula Na2O. This indicates that there are two sodium ions for each oxide ion in the compound, reflecting the stoichiometry necessary to achieve electrical neutrality.

Barium chloride is an ionic compound formed from barium and chlorine. Barium, a Group 2 element, has a +2 charge, while each chlorine atom, a Group 17 element, has a -1 charge. To balance the charges, one barium ion (Ba²⁺) combines with two chloride ions (Cl⁻), resulting in the formula BaCl₂. This reflects the stoichiometry necessary to achieve electrical neutrality in the compound.

Strontium sulfide is formed from strontium (Sr) and sulfur (S). Strontium, a group 2 alkaline earth metal, has a +2 oxidation state, while sulfur typically has a -2 oxidation state. To achieve electrical neutrality in the compound, one strontium ion combines with one sulfide ion, resulting in the formula SrS. This reflects the 1:1 ratio of strontium ions to sulfide ions, making SrS the correct formula for strontium sulfide.

Dinitrogen dioxide is a chemical compound consisting of two nitrogen atoms and two oxygen atoms. The formula N2O2 accurately represents this composition, indicating that there are two nitrogen (N) atoms bonded to two oxygen (O) atoms. This formula reflects the molecular structure of the compound, aligning with the naming convention where "di-" signifies two of each element present in the molecule.

Phosphorus pentachloride is a chemical compound formed by one phosphorus atom and five chlorine atoms. The prefix "penta-" in its name indicates the presence of five chlorine atoms bonded to the central phosphorus atom. This compound is commonly used in various chemical reactions and processes, particularly in organic synthesis. The formula PCl5 accurately represents the composition of the molecule, confirming that it contains one phosphorus and five chlorine atoms, aligning with the naming conventions of chemical compounds.

Calcium phosphate is a compound formed from calcium ions and phosphate ions. The formula Ca3(PO4)2 indicates that three calcium ions (Ca²⁺) combine with two phosphate ions (PO₄³⁻) to achieve charge neutrality. Each phosphate ion carries a -3 charge, while each calcium ion carries a +2 charge. Thus, three calcium ions provide a total charge of +6, which balances the -6 charge from two phosphate ions. This stoichiometric relationship reflects the correct proportions of calcium and phosphate in the compound, leading to the formula Ca3(PO4)2.

Static electricity refers to the accumulation of electric charge on the surface of a material, typically resulting from friction or contact with another substance. This build-up occurs when electrons are transferred between materials, leading to an imbalance of charge. Unlike current electricity, which involves the flow of electric charge through a conductor, static electricity remains stationary until discharged, often resulting in sparks or shocks. It is commonly observed in everyday situations, such as when rubbing a balloon on hair or when touching a metal object after walking on a carpet.

A conductor is a material that permits the flow of electric current due to the presence of free-moving charged particles, typically electrons. Metals like copper and aluminum are common examples of conductors, as they have low resistance and allow electricity to pass through easily. In contrast, insulators resist electrical flow, resistors limit current, and semiconductors have properties that can be modified to either conduct or insulate electricity under certain conditions. Thus, conductors are essential for electrical circuits and devices.

In electricity, the primary charge carriers that move through conductors are electrons. These negatively charged particles flow from the negative terminal to the positive terminal in a circuit, facilitating the flow of electric current. Protons, while positively charged, are bound within atomic nuclei and do not move freely in conductive materials. Neutrons are neutral and also remain within the nucleus. Ions can move in certain contexts, but in the context of conventional electrical current in conductors, electrons are the main particles responsible for movement and the transport of energy.

Resistance refers to the opposition that a substance offers to the flow of electric current. It is a fundamental property of materials, determining how easily electrons can move through them. High resistance means that the material impedes current flow, while low resistance allows it to pass more freely. This concept is crucial in electrical circuits, as it influences how much current flows when a voltage is applied. Understanding resistance helps in designing and analyzing electrical systems effectively.

Current refers to the flow of electric charge, specifically the movement of electrons through a conductor. It is measured in amperes and indicates how many electrons pass a given point in a circuit per second. In contrast, voltage measures the potential difference that drives the electrons, resistance quantifies how much a material opposes the flow of current, and power represents the rate at which energy is consumed or transferred. Thus, current is the term that directly describes the rate of electron movement.

Voltage represents the difference in electric potential energy per unit charge between two points in an electrical circuit. It quantifies how much energy is available to move charges from one point to another. In essence, voltage is the driving force that pushes electric current through a conductor, making it a fundamental concept in understanding electrical systems.

When one resistor is removed from a circuit, the total resistance decreases. According to Ohm's Law (V = IR), if the voltage remains constant, a decrease in resistance results in an increase in current. Therefore, the current flowing through the remaining resistor increases as there is less opposition to the flow of electricity, leading to a higher current through that resistor.

When cells are connected in series, their voltages add up. Each cell in this case provides 1.5 volts. Therefore, for three cells, the total voltage is calculated as follows: 1.5 V + 1.5 V + 1.5 V = 4.5 V. This cumulative effect results in a total voltage of 4.5 volts for the three cells connected in series.