Physical Science Module 12

An open circuit is a circuit that does not have a complete connection between the two sides of the power source. This means that there is a gap or break in the circuit, preventing the flow of current. Without a complete path for the current to follow, no electricity can flow through the circuit.

Charging by induction refers to the process of charging an object without direct contact between the object and a charge. This is achieved by bringing a charged object near the uncharged object, causing a redistribution of charges in the uncharged object. The presence of the charged object induces a separation of charges in the uncharged object, resulting in one side becoming positively charged and the other side becoming negatively charged. This method of charging is commonly used in various electronic devices and applications.

Two objects with opposite charges (negative and positive) will exert an attractive force towards each other. This is because opposite charges attract each other according to the fundamental principle of electrostatics. The negative charge will experience a force towards the positive charge, and vice versa. Therefore, the force exerted by these two objects will be toward each other.

Charging an object by allowing it to come into contact with an object that already has an electrical charge is called charging by conduction. This process involves the transfer of electrons from the charged object to the neutral object, resulting in both objects having the same charge. This is different from charging by induction, which involves the rearrangement of electrons within an object without direct contact with a charged object.

The correct answer is Electrical Current. Electrical current refers to the flow of electric charge, specifically the amount of charge that passes through a point in a circuit per unit of time. It is measured in amperes (A) and is essential for the functioning of electrical devices and systems. Conventional current, on the other hand, refers to the direction of flow of positive charge, which is opposite to the actual flow of electrons.

The current that flows from the positive side of the battery to the negative side is called conventional current. This term is used in circuit diagrams, even though it is technically incorrect. In reality, electrons flow from the negative side of the battery to the positive side. However, for the sake of simplicity and convention, current is shown as flowing in the opposite direction.

Resistance is the correct answer because it refers to the ability of a material to impede the flow of charge. It is a measure of how difficult it is for current to flow through a material. Resistance is typically measured in ohms and is determined by factors such as the material's conductivity and dimensions.

In conventional current flow, the flow of electric charge is considered to be from the positive terminal of the battery to the negative terminal. This convention was established before the discovery of the electron, and it is still used today for consistency and ease of understanding. Therefore, the correct answer is "Positive to Negative."

If both extension cords have the same current running through them, but the cord in the left hand is warmer than the one in the right hand, it suggests that the cord in the left hand has a higher resistance. According to Ohm's Law, resistance is directly proportional to the length of the wire and inversely proportional to its cross-sectional area. Since both cords are of equal length, the cord in the left hand must have a smaller cross-sectional area, indicating that it is thinner. Therefore, the cord in the right hand is thicker.

In a circuit, the amount of energy transferred is determined by both voltage and current. While voltage represents the potential energy per unit charge, current determines the rate at which the charge flows. Therefore, even if the voltage is low, a high current can compensate for it and result in a significant amount of energy being transferred in the circuit. This is why the statement is true.

Electron flow in a circuit runs from the negative end of the battery to the positive end. This is because electrons are negatively charged particles and are attracted to the positive terminal of the battery. Therefore, they move from the negative terminal, where there is an excess of electrons, towards the positive terminal, where there is a deficit of electrons. This flow of electrons is what creates an electric current in the circuit.

When a magnet is cut in half, each half becomes a new magnet with its own north and south poles. Therefore, cutting a magnet in half will result in two separate magnets, each with one north pole and one south pole. Hence, the answer is two north poles and two south poles.

If the atoms in an object are not aligned, it means that the object does not have a consistent magnetic field. A magnet is created when the atoms within an object are aligned in a way that produces a magnetic field. Therefore, if the atoms in an object are not aligned, it is not a magnet.

When the light bulbs are wired in parallel, each bulb has its own separate path to the power source. This means that if one bulb goes out, the current can still flow through the other bulbs, keeping them lit. In contrast, if the bulbs were wired in series, the failure of one bulb would break the circuit and cause all the other bulbs to go out as well. Therefore, the fact that the rest of the bulbs stay lit when one goes out indicates that the light bulbs are wired in parallel.

When two magnets have like poles (south and south) facing each other, the force between them is repulsive. This means that they exert a force that pushes them apart. If the distance between the magnets is suddenly doubled, the new force between them will still be repulsive. The repulsive force will remain the same, regardless of the distance between the magnets.

The object was charged by induction. This is because when a positively charged rod is brought near the object, the positive charges in the object are repelled and move away, leaving behind an excess of negative charges. This results in the object developing a negative charge. Induction occurs without direct contact between the charged rod and the object, which is why it is the correct explanation in this scenario.

The statement is false because a proton is not a "package" of light. A proton is a subatomic particle that carries a positive electric charge and is found in the nucleus of an atom. It is not related to light, which consists of photons.

When the distance between two magnets is doubled, the force between them decreases by a factor of 4. This is because the force between magnets is inversely proportional to the square of the distance between them. When the distance is doubled, the force decreases by a factor of 2 due to the inverse square law. Doubling the distance again will result in the force decreasing by another factor of 2, resulting in a total decrease of 4 times the original force.