Electric Current and Resistance Quiz

The rate of flow of electric charge. It's the amount of charge passing a point in a circuit per unit time.

The direction of current flow is assumed to be the direction a positive charge would move. However, in reality, electrons (negative charges) move in the opposite direction.

The SI unit of electric current, representing one coulomb of charge flowing per second.

The amount of charge passing a point in a circuit can be calculated by multiplying the current by the time.

The amount of electric charge that flows in a circuit. It's measured in Coulombs (C).

The duration over which the charge flows. It's measured in seconds (s).

The equation I = Q/t describes how current (I) is directly proportional to charge (Q) and inversely proportional to time (t).

You can use the equation I = Q/t to solve problems involving calculating charge, current, or time. Make sure to use the correct units.

The potential difference across two points in a circuit is the amount of energy required to move one coulomb of charge from one point to the other. The formula is potential difference = energy / charge.

The work done in moving a charge through a potential difference is calculated by multiplying the charge by the potential difference. The formula is work = charge x potential difference.

Electric current is defined as the rate of flow of charge. This means the amount of charge passing a point in the circuit per second. The formula for current is current = charge / time.

A voltmeter is used to measure the potential difference between two points in a circuit. It is always connected in parallel across the component being measured.

In a metal wire, electrons are the charge carriers. When an electric current flows, these negatively charged electrons move from the negative terminal of the battery towards the positive terminal, creating an electric current.

The amount of charge that flows through a circuit is directly proportional to the current and the time for which the current flows. The formula is charge = current x time.

In a series circuit, the current is the same at all points in the circuit. This is because the same amount of charge flows through each component in the circuit.

In a parallel circuit, the current divides between different branches of the circuit. This means the branch with the least resistance gets the most current. The total current entering the circuit is equal to the sum of currents in each branch.

A measure of how much a component opposes the flow of electric current. It's the ratio of potential difference across the component to the current flowing through it.

The relationship between voltage, current, and resistance in a circuit: Resistance equals Voltage divided by Current (R = V/I).

An electrical component designed to provide a specific resistance to the flow of current in a circuit.

The ohm (Ω). One ohm is the resistance when a current of one ampere flows through a component with a potential difference of one volt across it.

To control the size of the current flowing in a circuit. It helps to regulate the amount of electricity flowing through a component.

A resistor whose resistance can be adjusted. This allows you to change the current in a circuit by changing the value of resistance.

To calculate the resistance of a component, divide the potential difference across it by the current flowing through it.

Ohm's Law can be used to calculate any one of the three variables (voltage, current, or resistance) when the other two are known.

The quantity that remains constant in Ohm's Law, ensuring a direct proportionality between current and voltage.

A graph showing the relationship between current and voltage for a resistor, where the slope represents the resistance.

The resistance of a filament lamp changes with its temperature, increasing as it heats up.

Resistors connected in parallel offer multiple paths for current, reducing the overall resistance of the circuit.

The combined resistance of resistors in parallel is always less than the smallest individual resistance.

Resistors connected in series form a single path for current, adding up their individual resistances.

When identical resistors are connected in parallel, their combined resistance is the individual resistance divided by the number of resistors.

The circuit with the least total resistance allows the most current to flow for a given voltage.

You can calculate the resistance (R) of a material by dividing the voltage (V) applied across it by the current (I) flowing through it: R = V / I.

You can calculate the current (I) flowing through a material by dividing the voltage (V) applied across it by the resistance (R): I = V / R.

Temperature can affect the resistance of materials. For most conductors, resistance increases with temperature. For some materials, like semiconductors, resistance decreases with temperature.

To measure resistance, set up a circuit with a DC power supply, variable resistor, voltmeter connected across the material, and ammeter in series with it. Adjust the variable resistor to change the current and voltage readings.

Plot the voltage (V) on the y-axis and current (I) on the x-axis. The gradient of the line on this graph represents the resistance (R) of the material.

As the temperature of a filament lamp increases, its resistance also increases. This is due to the increased vibration of atoms, hindering electron flow.

A typical fixed resistor has a relatively constant resistance over a wide range of temperatures. This is because its material is chosen to minimize temperature effects.

Ohm's Law holds true for materials with constant resistance. However, some materials like semiconductors, diodes, and filament lamps do not follow Ohm's Law, meaning their resistance changes with voltage or current.

The opposition a wire offers to the flow of electric current. It depends on the wire's material, length, and cross-sectional area.

Several factors influence a wire's resistance:

• Length: Longer wires have higher resistance.
• Cross-sectional Area: Thicker wires have lower resistance.
• Material: Different materials have different resistance properties.
• Temperature: Resistance generally increases with temperature.

To increase the resistance of a wire, you can:

• Increase its length: A longer wire offers more opposition to current flow.
• Decrease its cross-sectional area: A thinner wire makes it harder for current to flow.

To decrease the resistance of a wire, you can:

• Decrease its length: A shorter wire offers less opposition to current flow.
• Increase its cross-sectional area: A thicker wire allows current to flow more easily.

A wire's resistance is directly proportional to its length and inversely proportional to its cross-sectional area. This means a longer wire has higher resistance, while a thicker wire has lower resistance.

In Ohm's Law, the current through a conductor is proportional to the voltage across it, but only if a specific quantity remains constant. This quantity is the resistance of the conductor.

Ohm's Law applies to a conductor when the relationship between current and voltage is linear, forming a straight line on a graph. This means the resistance remains constant over a range of voltages.

When resistors are connected in parallel, the total resistance decreases, making it easier for current to flow. This is because the current has multiple paths to choose from.

Resistors connected in series form a single path for current. The total resistance is the sum of the individual resistances of each resistor.

The circuit with the least total resistance allows the most current to flow for a given voltage. Think of the current as water flowing through a pipe; less resistance means more water can flow.

For most materials, resistance increases with temperature. This is because atoms vibrate more at higher temperatures, making it harder for electrons to flow through.